This happened yesterday, cant open any programs apart from the really basic windows stuff and internet explorer 64bit (not the other versions) Im running Windows 7 64bit (cant remember if its home premium or ultimate)
I can open regedit after a large amount of tinkering, as I'm assuming that whatever virus is causing this had disabled it. I cannot open system restore, although It was disabled before this happened and even If I could re enable it I dont think there would be any restore points. Im also experiencing random BSOD, usually during the welcome message load screen after logging in or about 5 to 10 minutes after log in. All of this happens whether or not im in safe mode.
To rule out anything else i've run a disk check on my hard drive and run memtest for about 5 hours. Neither of which found any errors. Its looking like I'll either need to repair windows with the installation disk (which I'm unsure of its current location) or fiddle with the registry some more, after some advice from anyone that will help me out!
I would really appreciate any help that be offered as I really need to get the PC working to do college work etc.