[3.0/LINQ] .NET Framework Problem

I'm still having that problem where I can't create or load new projects in C#. So I re-install the .NET Framework and then it works, but once I close the project or restart the computer, I have to download the .NET Framework again. How do I fix this?

Sounds like a major issue with your machine. It may be worth it to reinstall your OS and possibly do a format and reinstall.

Does it happen to the Framework only or to all other things that you are installing?