Ok. Can anyone point me in the direction as to why I am getting garbage values for User ID? And I am trying to use a for loop to read each struct off of the file and assign the values to arrays, but I don't know if this makes any sense. I was under the impression that this was the way to do it, unless I pull each struct and assign it a new struct?

AHHHHHH!!!! You guys are awesome! Thanks much for the help! I got it running, finished code is below if you care to run it.

#include <stdio.h>
#include <stdlib.h>
#define BUFFER 256
struct profile
{
  char user[10];
  char pass[10];
  char last[15];
  char first[15];
};
//prototypes
  void mainmenu(struct profile User [], int size, int *ucount);
  void signup(struct profile User [], int size, int *ucount);
  void signin(struct profile User [], int size, int *ucount);
  void adminSignup(struct profile User [], int size, int *ucount);
  void userSignup(struct profile User [], int size, int *ucount);
  int populate5(struct profile User []);
  int credentials(struct profile User [], int size, int *ucount, char userid[], char pass[]);
//endprotos
////////////////////////////////////////////////////////////////////////////////  
int main(int argc, char *argv[])
{
  //declarations
    int size = 15;//create 15 empty profiles
    struct profile User[size];
    int ucount = 0;//used for keeping track of the number of stored accounts
    char choice = ' ';
  
  ucount = populate5(User);//create 5 accounts
  do
  {//beginprog
    system("CLS");
    printf("********** Login Program **********\n");
    printf("1 -- Begin\n");
    printf("2 -- QUIT\n");
    printf("***********************************\n");\
    choice = getch();
    if(choice == '1') mainmenu(User, size, &ucount);
  }while(choice != '2');  
  system("CLS");	
  return 0;
}//endprog
////////////////////////////////////////////////////////////////////////////////
void mainmenu(struct profile User [], int size, int *ucount)
{
  //declarations
    char choice = ' ';
    
  do
  {//main menu
    system("CLS");
    printf("********** Main Menu **********\n");
    printf("1 -- Sign Up\n");//create profile
    printf("2 -- Sign In\n");//login
    printf("3 -- Back\n");
    printf("*******************************\n");
    choice = getch();
    switch(choice)
    {
      case '1' : signup(User, size, ucount);
                 break;
      case '2' : signin(User, size, ucount);
                 break;
      case '3' : break;
    }
  }while(choice != '3');
}
////////////////////////////////////////////////////////////////////////////////
void signup(struct profile User [], int size, int *ucount)
{
  //declarations
    char choice = ' ';
    
  do
  {//main menu
    system("CLS");
    printf("********** Sign Up **********\n");
    printf("1 -- Admin Sign Up\n");//admin creates profiles for users
    printf("2 -- User Sign Up\n");//user creates personal profile
    printf("3 -- Back\n");
    printf("*****************************\n");
    choice = getch();
    switch(choice)
    {
      case '1' : adminSignup(User, size, ucount);
                 break;
      case '2' : userSignup(User, size, ucount);
                 break;
      case '3' : break;
    }
  }while(choice != '3');
}
////////////////////////////////////////////////////////////////////////////////
void adminSignup(struct profile User [], int size, int *ucount)
{
  //declarations
    int i = 0;
    char userid[BUFFER] = {'\0'};
    char pass[BUFFER] = {'\0'};
    int attempt = 3;//allow 3 tries to login
    char choice = ' ';
    int success = 1;
    int a = 0;
    int len = 0;
    
  do
  {
    system("CLS");
    printf("Enter Admin userID >> ");
    fgets(userid, BUFFER, stdin);//admin username
    len = strlen(userid);
    if(userid[len - 1] == '\n') userid[len-1] = '\0';
    printf("\nEnter Admin password >> ");
    fgets(pass, BUFFER, stdin);//admin password
    len = strlen(pass);
    if(pass[len - 1] == '\n') pass[len-1] = '\0';   
    success = credentials(User, size, ucount, userid, pass);//authenticate
    if(success == 0)
    {//if entries are not correct
      attempt = attempt - 1;
      printf("\nIncorrect entry, you have %d attempts remaining\n",attempt);
      system("PAUSE");
      if(attempt == 0) return;
    } 
  }while(success == 0);
  do
  {//admin authenticated and can create profiles
    system("CLS");
    printf("********** Admin Sign Up **********\n");
    printf("There are %d empty profiles remaining\n", (size - *ucount));     
    printf("1 -- Create New User\n");
    printf("2 -- Back\n");
    printf("***********************************\n");
    choice = getch();
    switch(choice)
    {//enter account information
      case '1' : system("CLS");
                 printf("Enter User First Name >> ");
                 fgets(User[*ucount].first, BUFFER, stdin);
                 len = strlen(User[*ucount].first);
                 if(User[*ucount].first[len - 1] == '\n') User[*ucount].first[len-1] = '\0';    
                 printf("\nEnter User Last Name >> ");
                 fgets(User[*ucount].last, BUFFER, stdin);
                 len = strlen(User[*ucount].last);
                 if(User[*ucount].last[len - 1] == '\n') User[*ucount].last[len-1] = '\0';
                 printf("\nEnter User ID >> ");
                 fgets(User[*ucount].user, BUFFER, stdin);
                 len = strlen(User[*ucount].user);
                 if(User[*ucount].user[len - 1] == '\n') User[*ucount].user[len-1] = '\0';    
                 printf("\nEnter User Password >> ");
                 fgets(User[*ucount].pass, BUFFER, stdin);
                 len = strlen(User[*ucount].pass);
                 if(User[*ucount].pass[len - 1] == '\n') User[*ucount].pass[len-1] = '\0';    
                 *ucount = *ucount + 1;
                 if(*ucount == size)
                 {//if all structures allocated by -size- are filled
                   printf("No more profiles available.");
                   system("PAUSE");
                   system("CLS");
                   return;
                 }
                 break;
      case '2' : break;
    }
  }while(choice != '2');      
}  
////////////////////////////////////////////////////////////////////////////////
void userSignup(struct profile User [], int size, int *ucount)
{
  char choice = ' ';
  int len = 0;
  do
  {//user creates personal profile
    system("CLS");
    printf("********** New User Sign Up **********\n");     
    printf("1 -- Create New User\n");
    printf("2 -- Back\n");
    printf("**************************************\n");
    choice = getch();
    switch(choice)
    {
      case '1' : system("CLS");
                 printf("Enter User First Name >> ");
                 fgets(User[*ucount].first, BUFFER, stdin);
                 len = strlen(User[*ucount].first);
                 if(User[*ucount].first[len - 1] == '\n') User[*ucount].first[len-1] = '\0';    
                 printf("\nEnter User Last Name >> ");
                 fgets(User[*ucount].last, BUFFER, stdin);
                 len = strlen(User[*ucount].last);
                 if(User[*ucount].last[len - 1] == '\n') User[*ucount].last[len-1] = '\0';
                 printf("\nEnter User ID >> ");
                 fgets(User[*ucount].user, BUFFER, stdin);
                 len = strlen(User[*ucount].user);
                 if(User[*ucount].user[len - 1] == '\n') User[*ucount].user[len-1] = '\0';    
                 printf("\nEnter User Password >> ");
                 fgets(User[*ucount].pass, BUFFER, stdin);
                 len = strlen(User[*ucount].pass);
                 if(User[*ucount].pass[len - 1] == '\n') User[*ucount].pass[len-1] = '\0';
                 *ucount = *ucount + 1;
                 if(*ucount == size)
                 {
                   printf("No more profiles available.");
                   system("PAUSE");
                   system("CLS");
                   return;
                 }
                 break;
      case '2' : break;
    }
  }while(choice != '2');       
}     
////////////////////////////////////////////////////////////////////////////////
int credentials(struct profile User [], int size, int *ucount, char userid[], char pass[])
{
  //declarations  
    int i = 0;
    int a = 0;
    int b = 0;
  
  do
  {//checks pointer to array of user input against Stucture arrays
    if(strcmp(userid, User[i].user) == 0) a = 1;//if all characters match, activate flag -a-  
    if(strcmp(pass, User[i].pass) == 0) b = 1;//if all characters match, activate flag -b-   
    if(a == 1 && b ==1) 
    {
      printf("\Login Successful!\n\n");
      system("PAUSE");
      return 1;//if flags -a- and -b- match, validation successful
    }
    else i++;//otherwise move to next account to check againsti++; 
  }while(i<size);
  return 0;
}
  
////////////////////////////////////////////////////////////////////////////////
void signin(struct profile User [], int size, int *ucount)
{
  //declarations
    int i = 0;
    char userid[BUFFER] = {0};
    char pass[BUFFER] = {0};
    int attempt = 3;
    int success = 1;
    int len = 0;
 
  do
  {//same as admin login, validate input vs stored
    system("CLS");
    printf("Enter userID >> ");
    fgets(userid, BUFFER, stdin);
    len = strlen(userid);
    if(userid[len - 1] == '\n') userid[len-1] = '\0';
    printf("\nEnter password >> ");
    fgets(pass, BUFFER, stdin);
    len = strlen(pass);
    if(pass[len - 1] == '\n') pass[len-1] = '\0';
    success = credentials(User, size, ucount, userid, pass);
    if(success == 0)
    {
      attempt = attempt - 1;
      printf("\nIncorrect entry, you have %d attempts remaining\n",attempt);
      system("PAUSE");
      if(attempt == 0) return;
    } 
  }while(success == 0);
}  
////////////////////////////////////////////////////////////////////////////////
int populate5(struct profile User [])
{//hardcoded accounts, including admin
  strcpy(User[0].first,"John");
  strcpy(User[0].last,"Madden");
  strcpy(User[0].user,"Admin");
  strcpy(User[0].pass,"Pwd");
  
  strcpy(User[1].first,"John");
  strcpy(User[1].last,"Mathews");
  strcpy(User[1].user,"JM561");
  strcpy(User[1].pass,"AAA");
  
  strcpy(User[2].first,"Laura");
  strcpy(User[2].last,"Candy");
  strcpy(User[2].user,"LC968");
  strcpy(User[2].pass,"BBB");
  
  strcpy(User[3].first,"Mark");
  strcpy(User[3].last,"Johnson");
  strcpy(User[3].user,"MJ185");
  strcpy(User[3].pass,"CCC");
  
  strcpy(User[4].first,"Mike");
  strcpy(User[4].last,"Harrison");
  strcpy(User[4].user,"MH115");
  strcpy(User[4].pass,"DDD");
  
  return 5;  
}     

Thanks for the replies! Ok, I re-wrote the code as it is below, but now it completely stops working after entering the credentials I changed the code in the credentials function to use strcmp() as well as changed the user input with strlen() to get rid of the '\n' at the end of it.

#include <stdio.h>
#include <stdlib.h>
#define BUFFER 256
struct profile
{
  char user[10];
  char pass[10];
  char last[15];
  char first[15];
};
//prototypes
  void mainmenu(struct profile User [], int size, int *ucount);
  void signup(struct profile User [], int size, int *ucount);
  void signin(struct profile User [], int size, int *ucount);
  void adminSignup(struct profile User [], int size, int *ucount);
  void userSignup(struct profile User [], int size, int *ucount);
  int populate5(struct profile User []);
  int credentials(struct profile User [], int size, int *ucount, char *USER, char *PASS);
//endprotos
////////////////////////////////////////////////////////////////////////////////  
int main(int argc, char *argv[])
{
  //declarations
    int size = 15;//create 15 empty profiles
    struct profile User[size];
    int ucount = 0;//used for keeping track of the number of stored accounts
    char choice = ' ';
  
  ucount = populate5(User);//create 5 accounts
  do
  {//beginprog
    system("CLS");
    printf("********** Login Program **********\n");
    printf("1 -- Begin\n");
    printf("2 -- QUIT\n");
    printf("***********************************\n");\
    choice = getch();
    if(choice == '1') mainmenu(User, size, &ucount);
  }while(choice != '2');  
  system("CLS");	
  return 0;
}//endprog
////////////////////////////////////////////////////////////////////////////////
void mainmenu(struct profile User [], int size, int *ucount)
{
  //declarations
    char choice = ' ';
    
  do
  {//main menu
    system("CLS");
    printf("********** Main Menu **********\n");
    printf("1 -- Sign Up\n");//create profile
    printf("2 -- Sign In\n");//login
    printf("3 -- Back\n");
    printf("*******************************\n");
    choice = getch();
    switch(choice)
    {
      case '1' : signup(User, size, ucount);
                 break;
      case '2' : signin(User, size, ucount);
                 break;
      case '3' : break;
    }
  }while(choice != '3');
}
////////////////////////////////////////////////////////////////////////////////
void signup(struct profile User [], int size, int *ucount)
{
  //declarations
    char choice = ' ';
    
  do
  {//main menu
    system("CLS");
    printf("********** Sign Up **********\n");
    printf("1 -- Admin Sign Up\n");//admin creates profiles for users
    printf("2 -- User Sign Up\n");//user creates personal profile
    printf("3 -- Back\n");
    printf("*****************************\n");
    choice = getch();
    switch(choice)
    {
      case '1' : adminSignup(User, size, ucount);
                 break;
      case '2' : userSignup(User, size, ucount);
                 break;
      case '3' : break;
    }
  }while(choice != '3');
}
////////////////////////////////////////////////////////////////////////////////
void adminSignup(struct profile User [], int size, int *ucount)
{
  //declarations
    int i = 0;
    char userid[BUFFER] = {'\0'};
    char pass[BUFFER] = {'\0'};
    int attempt = 3;//allow 3 tries to login
    char choice = ' ';
    int success = 0;
    int a = 0;
    int len = 0;
    
  do
  {
    system("CLS");
    printf("Enter Admin userID >> ");
    fgets(userid, BUFFER, stdin);//admin username
    len = strlen(userid);
    if(userid[len - 1] == '\n') userid[len-1] = '\0';
    printf("\nEnter Admin password >> ");
    fgets(pass, BUFFER, stdin);//admin password
    len = strlen(pass);
    if(pass[len - 1] == '\n') pass[len-1] = '\0';   
    char *USER = userid;
    char *PASS = pass;    
    success = credentials(User, size, ucount, USER, PASS);//authenticate
    if(success == 0)
    {//if entries are not correct
      attempt = attempt - 1;
      printf("\nIncorrect entry, you have %d attempts remaining\n",attempt);
      system("PAUSE");
      if(attempt == 0) return;
    } 
  }while(success == 0);
  do
  {//admin authenticated and can create profiles
    system("CLS");
    printf("********** Admin Sign Up **********\n");
    printf("There are %d empty profiles remaining\n", (size - *ucount));     
    printf("1 -- Create New User\n");
    printf("2 -- Back\n");
    printf("***********************************\n");
    choice = getch();
    switch(choice)
    {//enter account information
      case '1' : system("CLS");
                 printf("Enter User First Name >> ");
                 fgets(User[*ucount].first, BUFFER, stdin);
                 len = strlen(User[*ucount].first);
                 if(User[*ucount].first[len - 1] == '\n') User[*ucount].first[len-1] = '\0';    
                 printf("\nEnter User Last Name >> ");
                 fgets(User[*ucount].last, BUFFER, stdin);
                 len = strlen(User[*ucount].last);
                 if(User[*ucount].last[len - 1] == '\n') User[*ucount].last[len-1] = '\0';
                 printf("\nEnter User ID >> ");
                 fgets(User[*ucount].user, BUFFER, stdin);
                 len = strlen(User[*ucount].user);
                 if(User[*ucount].user[len - 1] == '\n') User[*ucount].user[len-1] = '\0';    
                 printf("\nEnter User Password >> ");
                 fgets(User[*ucount].pass, BUFFER, stdin);
                 len = strlen(User[*ucount].pass);
                 if(User[*ucount].pass[len - 1] == '\n') User[*ucount].pass[len-1] = '\0';    
                 *ucount = *ucount + 1;
                 if(*ucount == size)
                 {//if all structures allocated by -size- are filled
                   printf("No more profiles available.");
                   system("PAUSE");
                   system("CLS");
                   return;
                 }
                 break;
      case '2' : break;
    }
  }while(choice != '2');      
}  
////////////////////////////////////////////////////////////////////////////////
void userSignup(struct profile User [], int size, int *ucount)
{
  char choice = ' ';
  int len = 0;
  do
  {//user creates personal profile
    system("CLS");
    printf("********** New User Sign Up **********\n");     
    printf("1 -- Create New User\n");
    printf("2 -- Back\n");
    printf("**************************************\n");
    choice = getch();
    switch(choice)
    {
      case '1' : system("CLS");
                 printf("Enter User First Name >> ");
                 fgets(User[*ucount].first, BUFFER, stdin);
                 len = strlen(User[*ucount].first);
                 if(User[*ucount].first[len - 1] == '\n') User[*ucount].first[len-1] = '\0';    
                 printf("\nEnter User Last Name >> ");
                 fgets(User[*ucount].last, BUFFER, stdin);
                 len = strlen(User[*ucount].last);
                 if(User[*ucount].last[len - 1] == '\n') User[*ucount].last[len-1] = '\0';
                 printf("\nEnter User ID >> ");
                 fgets(User[*ucount].user, BUFFER, stdin);
                 len = strlen(User[*ucount].user);
                 if(User[*ucount].user[len - 1] == '\n') User[*ucount].user[len-1] = '\0';    
                 printf("\nEnter User Password >> ");
                 fgets(User[*ucount].pass, BUFFER, stdin);
                 len = strlen(User[*ucount].pass);
                 if(User[*ucount].pass[len - 1] == '\n') User[*ucount].pass[len-1] = '\0';
                 *ucount = *ucount + 1;
                 if(*ucount == size)
                 {
                   printf("No more profiles available.");
                   system("PAUSE");
                   system("CLS");
                   return;
                 }
                 break;
      case '2' : break;
    }
  }while(choice != '2');       
}     
////////////////////////////////////////////////////////////////////////////////
int credentials(struct profile User [], int size, int *ucount, char *USER, char *PASS)
{
  //declarations  
    int i = 0;
    int a = 0;
    int b = 0;
  
  do
  {//checks pointer to array of user input against Stucture arrays
    if(strcmp(*USER, User[i].user) == 0)
    {
      a = 1;//if all characters match, activate flag -a-
    }  
    else
    {//otherwise move to next account to check against
      i++;
    } 
  }while(i<size);
  do
  {//same as above, checking validation of input password against stored password
    if(strcmp(*PASS, User[i].pass) == 0)
    {
      b = 1;//if all characters match, activate flag -b-
    }  
    else
    {
      i++;
    }
    if(a == 1 && b ==1) return 1;//if flags -a- and -b- match, validation successful 
  }while(i<size);  
  return 0;
}
  
////////////////////////////////////////////////////////////////////////////////
void signin(struct profile User [], int size, int *ucount)
{
  //declarations
    int i = 0;
    char userid[BUFFER] = {0};
    char pass[BUFFER] = {0};
    int attempt = 3;
    int success = 0;
    int len = 0;
 
  do
  {//same as admin login, validate input vs stored
    system("CLS");
    printf("Enter userID >> ");
    fgets(userid, BUFFER, stdin);
    len = strlen(userid);
    if(userid[len - 1] == '\n') userid[len-1] = '\0';
    printf("\nEnter password >> ");
    fgets(pass, BUFFER, stdin);
    len = strlen(pass);
    if(pass[len - 1] == '\n') pass[len-1] = '\0';
    char *USER = userid;
    char *PASS = pass;
    success = credentials(User, size, ucount, USER, PASS);
    if(success == 0)
    {
      attempt = attempt - 1;
      printf("\nIncorrect entry, you have %d attempts remaining\n",attempt);
      system("PAUSE");
      if(attempt == 0) return;
    } 
  }while(success == 0);
  printf("Successful Login!");
  system("PAUSE");
  return;
}  
////////////////////////////////////////////////////////////////////////////////
int populate5(struct profile User [])
{//hardcoded accounts, including admin
  strcpy(User[0].first,"John");
  strcpy(User[0].last,"Madden");
  strcpy(User[0].user,"Admin");
  strcpy(User[0].pass,"Pwd");
  
  strcpy(User[1].first,"John");
  strcpy(User[1].last,"Mathews");
  strcpy(User[1].user,"JM561");
  strcpy(User[1].pass,"AAA");
  
  strcpy(User[2].first,"Laura");
  strcpy(User[2].last,"Candy");
  strcpy(User[2].user,"LC968");
  strcpy(User[2].pass,"BBB");
  
  strcpy(User[3].first,"Mark");
  strcpy(User[3].last,"Johnson");
  strcpy(User[3].user,"MJ185");
  strcpy(User[3].pass,"CCC");
  
  strcpy(User[4].first,"Mike");
  strcpy(User[4].last,"Harrison");
  strcpy(User[4].user,"MH115");
  strcpy(User[4].pass,"DDD");
  
  return 5;  
}     

Yeah, the COP1000 taught the basic structure of how code looks in IDEs by starting us off with pseudocode. COP2220 is an intro to pure C programming. Honestly, I have no idea what languages to pursue. My dad programs in COBOL for a financial company, and I learned the basics of BASIC about 10 years ago.