Computer freezes at Windows XP screen and safe mode?

Yesterday I noticed my Dell desktop computer was freezing at the windows xp screen. I tried several times to restart it and get it back to normal. After several failed attempts I tried to run it in safe mode. When I try safe mode - networking or safe mode command prompt it freeze at the partition(1)\WINDOWS\System32\Drivers\Mu… When I try to run regular safe mode the computer shuts down and gives me an alert saying it shoutdown because of thermal failure when I restart. I know this is a virus and I am trying to get to it. Is there anyway to do this since I can't get into safe mode? I have a genuine install of Windows XP Professional on my system but cannot locate my install CD. PLEASE help me.