now this is my friend's laptop so the description is wat he gave me ,he thought he had some viruses,was already running an av,installed Bit Defender Total Security 2008 on top of that,ran bit defender,it quarentined some stuff,dont know wat as I wasnt there,now the problem is ..as soon as he logs on to winxp,instantly the screen saying "windows is shutting down" pops up and laptop powers down..tried going into safe mode but same problem,cant even stay logged on long enough to uninstall Bit Defender,shutdown is instantaneous...any help would b most appreciated...many thanks