Xp Re-booting

I have an HP Paqvillion ze5500 laptop with XP.It won't boot up completely. It boots up to the Windows Xp logo, and runs for about twenty seconds after that, then shuts down and does it all over again. I tried to start it in safe mode, and after I hit the enter key it shows a list of files loading, and then shuts down after about twenty seconds and tries to boot again. The fan is running properly so I don't think it is a heat problem. I can leave it in the Windows Advanced Options Menu for safe mode for hours and it doesn't shut down, but as soon as I hit the enter key to start in safe mode it shuts down in about twenty seconds and tries to re-boot again. I inserted my Windows XP CD and started in Recovery Console to do a system restore, but Windows XP doesn't allow a restore in Recovery Console, so I was wondering if anyone has any ideas, or has had this problem too. Thanks in advance. RonH

I fixed the problem. I inserted the XP setup disk, pressed F8, then pressed R for repair, and it took care of the problem. RonH