My PC is have following problems, please advice me how to fix them: 1. Windows XP (SP2) security center can not open. 2. Task manager does not show any processes running. 3. Unti-virus program Avast! can not update 4. Regedit.exe can not be opened. 5. Windows can not auto-update 6. Another strange thing is, when I try searching the term “security center” on Google using either IE or Firefox, the browser will automatically close. Same things happed when I try to search the popular unti-virus software names. I tried using Ad-ware and Spy-bot but no success, now I have uninstalled the Windows SP2. One urgent question is, if I backup my data (like pictures and DV clips) now, will it be infected. Thanks a lot for help.