Working on a friend's computer - Dell Desktop with Windows Vista Home Basic. On boot up, this message appears: When I select "OK", the computer tries to reboot and I get a log on option but when I select it, I get the above message again - a loop. The computer owner doesn't recall any significant event that would have caused any problem (not a sophisticated computer user - and doesn't remember any passwords). I am able to boot into "Safe" mode and do a few things. However, it appears that Windows Explorer has disappeared. I went to Task Manager and typed in "Explorer.exe" in the Run box and got nothing. I had thoughts of running this by Broni in Malware but I can't make the Farbar app run. By clicking on "Computer" and then double clicking on the C drive, I was able to get to her documents and copy them to a flash drive so I hope I have them rescued. Any suggestions on what I can do to kick start this thing? Update - Just checked and the Security is turned off and I can't turn it back on. Says "The Security Center service can't be started".