My OS is Windows Vista Ultimate. When I tried to install some programs which require .NET Framework 2.0, the program cannot neither finish the installation nor run. The software providers tested the software carefully with Windows Vista and some users can use the software without any error. The problem remains the corruption or any bug in .NET Framework 2.0. How can I restore it to original version, or reinstall .NET Framework 2.0 ? Is there any bug fix which I need to update ?