Yep did that, twice. The second time I made sure all coresponding folders were removed and I spent about 3 hours manually removing all Visual Studio, MSBuild, and .NET Frame work registry entries I could find. It's amazing even Microsoft doesn't know how to clean the registry (that they made) when you uninstall their software.
Your machine is heavily broken and all your fixes are only going to make your life worse. Visual Studio 2010 works with MSBuild 4.0, and shoehorning in 3.5 is just asking for trouble.
Visual Studio is as close as it comes to "It just works" as development tools get, especially one of it's complexity. It sounds like you have a bad .NET install. I would uninstall everything and reinstall Visual Studio from scratch.
Maybe later when I am burnt out form reading up on CMake and makefiles I'll think about trying one last time to get Visual Studio installed. I will have to revert back to a restore point prior to the first install. Unfortunately that is going to wipe out some software and several updates I did after installing Visual Studio.
Wish I could, I would have sworn gremlins was a system requirement for using Microsoft products... No wait, gremlins is one of the support packages they install.
Kill the gremlins living in your PC.