XP: Reboot Loop

Ok. I looked all over and I couldn't find any help. I have a computer that was attacked by a virus that messed it up really bad. I finally got that out, but I have a new problem now. It gets to the part where it's loading Windows XP Home Edition (It's a compaq persario 5000) and the little green bar will go across and then it just restarts. When I put my CD in, it restarts in a shorter amount of time. I finally got it to where it completes the install, and I put the CD in, and it restarts AGAIN! Please help. I'm ready to let it meet Mr. Rock. Which is in my closet somewhere. Also, I tried a repair, I redid the partitions, and tried everything in F8. Still doesn't work. IT'S DEFECTIVE!