This is very similar to the problem in this question: http://social.technet.microsoft.com/Forums/en-US/w7itprogeneral/thread/ec4728c3-0e2a-4551-82e4-ec59888bf67c The full story is this: two days ago (4/19) I installed some updates before shutting down my computer for the night, including optional ones. After the updates finished on boot up the next morning (4/20) everything was fine for most of the day. However last night I started having trouble switching windows and interacting with the taskbar and desktop. Basically, I can interact with one window, but after using it for a few seconds I can't interact with the taskbar or any other window accessed by alt-tabbing. If I want to be able to click on a different window I have to ctrl-alt-del, click cancel, then I have a few seconds to select the window I want. It's super annoying. Here are the things I've already tried: I've scanned for malware and viruses (didn't find any), cleaned the registry, uninstalled (still had the problem)and reinstalled the updates, ran sfc (didn't find anything), created a new user (had the same problem), tried doing a clean boot (still had the problem) and doing the same thing with ShellExView with no better luck. The bad news: For whatever reason, I don't have a restore point before the updates on 4/19. I'm not sure why, but the point is moot. Currently, I have all available updates installed except Microsoft Silverlight and Internet Explorer 9, neither of which I use or have previous versions installed. The solutions I tried were all I could find online. Is there anything else, or am I going to have to reinstall Windows? Any help is greatly appreciated. Thanks!

Hi, Since you have tried many tests but failed, also there is no system restore point, you can try to login with Safe Mode or last good known configuration to see if the same issue occurs. If the issue persists, the last way you can try to perform an in-place upgrade to fix the issue: http://support.microsoft.com/kb/2255099 Hope that helps. Regards, Leo Huang Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.