Installing .NET Framework 3.5 Service Pack 1 on Windows Vista x64, even when it's the only program installed plus the updates seems to cause a fatal file association error with XPS Viewer in Windows Vista 64 Bit (doesn't affect Vista 32 Bit) which result in the lost of the default file association, original icon shortcut and a complete uninstall don't take care of the problem. I need Framework 3.5 SP1 because I use SQL Server 2008 Developer (thanks to Dreamspark program) for my personal database needs.
I don't know where to look, I tried editing the registry for the issue, but it don't work. It says that the files are currently in use (where?) and that the values can't be taken in charge.