What is the Microsoft component that is being added?

Microsoft Visual C++ Runtime

I'm using the free edition and don't know much about computers. What is the purpose of having that component installed now and not when I originally installed the program?

When the programmers make Ad-Aware (or any other program) they give the program instructions - eg. "open a new window on the screen".

Ad-Aware is written using MS Visual C++ so some of the instructions it uses need that - eg. "use function xyz from Visual C++"

Hope that's understandable...

If not post back and I'll try and explain again