I have a botched Windows 7 thanks to several failed .NET 4.0 attempts. At the root of the issue seems to be some confusion over credentialing - the rig was stable for a couple of years until the .NET 4 fiasco[s] but now can't run MSI's, can't create any alternate user accounts and successfully login/configure.
anyone want to guess as to whether a repair install will remedy this? I may as well try... can't get too much worse