How can I get computer to stop continually booting up, so I can troubleshoot it?

This computer continues to boot up and whether I try to pick "Start Normally " or any of the safe modes it continues to cycle through and never stop. At some point before the big windows XP pops up on the screen, a screen with a blue background and some writing pops up, but it is so quick, you can't make out a single word or hit whatever key it is to stop it there. So I obviously cannot get any further to troubleshoot this computer, I can only imagine what I'm going to find. Does this make sense?

 

Pause key didn't work.

 

Tap f8 and select Disable Automatic restart on system failure on the screen you would normally select safe mode at.

 

The last time I had that problem, the CPU was getting too hot, because the fan had failed...have you checked your cpu temp, and fans to make sure everything is operating correctly?

 

Heat would only be a factor if the computer was in use after a couple of minutes, I'd be more inclined to think you got a nasty bug somewhere.

This might help get you started,
http://www.techmixer.com/free-bootable-antivirus-rescue-cds-download-list/

Hope this helps.