Automatic restart - computer will not boot! :(

Computer Gurus-

Here is my situation. I turn on my computer, it goes to the loading windows xp screen, then reboots before it gets to loading even the slightest hint of the actual windows OS.

So I tried my solution. I attempted to boot from CD drive, with the windows xp install cd in the drive, attempted to re-install/repair my installation of windows. It copied the setup files to the computer, and said that it "will now restart and setup will continue". So my computer restarts, gets to the loading windows xp screen in dos, loads up to an all blue screen with a curser on it, then restarts. I've tried several times, and this occurs each time exactly as stated.

I have already ran chkdsk and no errors were found.

This is an "all of the sudden" issue. My computer has sat in my closet (a dust free environment) for about a year, having moved and it was in perfect working order upon arrival. I took it out of the closet a couple months ago, booted it up normally, played some music, then stuck it back into the closet. Only recently did I re-take it out, and have had these issues.

I hope I've given enough background as possible.

It keeps restarting to no avail. I am not sure weather this is a HD problem, a loose cable problem. My fan is in operable condition so I cannot see it being an overheating problem. Suggestions and solutions welcome!

Most appreciative,
Jon