I don't see how your WAMP installation would be influenced by installing the .Net runtime (1.0,1.1, 2.0 or 3.0?)
What i can imagine is that you ended up with a webserver (eg: IIS or Casinni (used by visual studio)) that already uses the port your Apache is trying to use....
I have Wamp + MS Visual Studio on my PC. But VS was installed earlier.
Don't know if the order is important. But these soft can be installed at the same PC - it's for sure.