My computer would start up and then lock after one or two minutes. I narrowed down the problem to a System Restore error. I turned off System Restore then turned it back on. The machine froze as soon as it was turned back on. I went into recovery console and deleted sr.sys from the C:\windows\system32\drivers directory and the machine booted and worked flawlessly, albeit without a functioning System Restore. I tried reinstalling SR via the sr.inf file and it seemed to install ok, but then the machine froze again. After reboot, I could not get past the logon screen. I re-deleted sr.sys and it was fine again. I then did a repair install of XP and could not get past the login screen. Once again I deleted sr.sys and it is now fine. Does anybody have a clue what's going on here as it is driving me nuts? Thanks.