QUOTE(Quin @ 6 Jul, 2009 - 06:55 AM)

Ok
So I can use ASP.NET to interact with the server and database, basically by using forms (as you can do with PHP and HTML).
With MS Web Developer, pages are saved as .aspx (I think).
I'm used to .html and .php
But, what you are saying is that ASP.NET is a framework and I can do whatever on top of it and to my website.
This includes adding Flash and Java. And in order for them to respond to the database, I don't use ASP.NET.
First, yes, ASP.NET pages are saved as .aspx
Second, yes, you can use ASP.NET to interact with the server.
Just like you can embed Flash in an HTML page you can do the same with ASP.NET. If you look at the source code of an ASP.NET page, much of it is the same as HTML(not exactly though). You have div's and table's and span's, etc.
ASP.NET pages can also have C# or VB.NET code associated with them. When the user clicks on a button, you can create an event handler like you would do in a Window's form and create code to handle that event, like submitting a call to retrieve a record from a database.
Why not go to:
http://msdn.micosoft.com/en-us/default.aspxand look at the source code for the page.(I chose that one because it was the first one that came to mind when I was thinking of ASP.NET web pages.) You will see many common elements to HTML. I might get flack for saying this but you can think of ASP.NET as adding to HTML in a server context, like Javascript adds to HTML in a client context.
You may want to visit the ASP.NET forum and ask a few questions there about ASP.NET, they will have better answers to your questions.