It's not easy to explain the difference between ASP and ASP.NET, but the second is object oriented and all the element of the page are object.
In ASP.NET you can use the language you want to use to prodece the page (VB.NET or C#).
All the code is in a particular file that is not including in the web pages and you must recompiling when you make changes, because ASP.NET using compiling language.
The compiling of the page was made at the server the first time and in the next run reuse this compiling result.
This is a simple introduction to the differnce between this two language, but is not sufficient to define the difference of this two languages.