[eXplosiv]

.data
appname db"simple program",0
.code
start:
mov eax,23
again:
div eax,2
mov bx,dx
shr edx,1
.if eax!=0
jmp again
.else 
invoke MessageBox,addr NULL,edx,addr appname,MB_OK
invoke ExitProcess,NULL
.endif
end start

what is the problem in the code it does not return answer in message box

[GunnerInc]

invoke MessageBox,addr NULL,edx,addr appname,MB_OK

First parameter is a HANDLE to the MessageBox parent (or NULL for the desktop) JUST NULL not ADDR NULL. Second parameter is a pointer to a null terminated string, NOT a number, so you will have to convert the number in ebx to a string. Looks like you are using MASM, if you are there is a function called dwtoa (DWORD to ASCII) that you could use.

also div eax,2 is not a valid syntax for div