DON'T DO IT !! I have Vista Bus. x32 and have my notebook set to notify me about the updates. The only update was this one KB951847 Microsoft .NET Framework 3.5 Service Pack 1 and.NET Framework 3.5 Family Update x86. It seemed to load ok, said needs to reboot and put my notebook into an endless reboot loop to the Stage 3 installation -- went to 99% and rebooted, started over and over and over. I let it uns an hours#%($# Microsoft. Wish they would test these things. Now to go fix it - I am typing this on my VISTA x64 desktop.