I have a Dimension 3000 and when I booted the other day, it would start loading then reboot itself.  I tried to boot in safe mode but the same thing keeps happening.  I tried GOBack and that doesn't work either.  My system just keeps rebooting itself.  Both fans on the system are operating fine.  Dell sent me the XP disk and I tried to repair my hard drive to remove any viruses there might be.  However, when I boot from the cd it asked for an administrative password.  I do not have one.  I didn't put one on my system.  I really don't want to wipe my hard drive.