Been running fine for 6 months, logged on ok with no password prompts. Installed mozilla and then removed it and ie6 wouldn't run so went to install it from this site. Wouldn't log on to windows so went to do virus check, removed viruses and restarted machine and all's I get is the log onto windows box, username set to Administrator, I leave password blank press enter and it accepts and says loading personal settings, logging on and then immidiatley makes the logging off/shutdown noise and returns to the log on to windows box. Tried pressing f1/12 to reset boot order and put xp disc in and let it run and it ends up saying STOP: c0000221 unknown hard error\SystemRoot\System32\ntdll.dll. Noted the various password posts in the forums but none answer this. I can only presume it's a virus. I thought bye putting the xp disc in and booting the cd drive first I could just reinstall xp, but cant, as per the error message. I also have to maually turn off the pc as it freezes at that message. Firstly can anyone suggest why the log on box just appeared out of nowhere, as no one has played around with settings, could a virus do this?? 2 how do I delete/defrag my drive and reinstall xp with my boot disk?? thanks

This is a Windows 7 forum. Best to repost your question in a WinXP newsgroup.