Recently, I have been running into some applications errors that can be traced back to corrupt .Net (dotNet) file(s).
In some cases, using the “normal” Add/Removed (appwiz.cpl) will work, but in some EXTREME cases, you might need a little more.
Aaron Stebner has an application for you!
.NET Framework Cleanup Tool User’s Guide
As Aaron mentions in his blog and guide, this tools will get rid of EVERYTHING, so before you use it, make sure you have installers available to you for the versions that you are deleting!