Hard Drive keeps rebooting

I am running Windows XP SP3. I tried to boot my computer and it just boots up to the Windows XP screen and starts all over again. I put another hard drive in it to see what would happen. Same thing. The spare hard drive i used does have an OS on it.
I put the Windows XP cd in and it just freezes at the "boot from cd" screen.
I ran barts pc cd. And it sees the hard drive and everything on it. I just cant boot up. Any suggestions on what direction I need to go?
Also will not even boot to safe mode or to command prompt.

 

I would recommend burning Memtest to a CD and running it overnight as a starting point: http://memtest.org

 

Went to http://memtest.org/. Is that for testing my RAM? If so, i had some spare sticks i installed and didn't help.
This is really frustrating. I can see everything on the hard drive with Barts PE, it just won't boot to it.

 

Yes, this is for testing RAM. Installing more sticks will not help if the ones in there at the start are faulty.

 

Sorry I wasn't more clear. I did replace the ram with 2 other sticks. Still no luck.

 

Okay, then. Please download and try to run ubuntu from a CD to see if that will boot: http://www.ubuntu.com/