Restarting after bios screen - loop

I have a problem with my PC, I still use XP on it.

I took the hard drive out and plugged it into my external dock on my laptop - ran PC Tools Internet Security and cleared up all the rubbish on it.

I hooked the hard drive back up to the computer and it came up saying NTLDR missing, so I fixed it by copying the file from the xp cd backover to the hard drive, then done a chkdsk , then fixboot, then fixmbr.

Now it turns on, gets past the bios boot screen and restarts, if I keep tapping F8 the boot options come up with safe mode etc, but no matter what one I choose it just restarts.

Any suggestions? don't really want to reformat the hard drive - so any suggestions would be great

 

Do you have a windows disc and a drive that can read it in that computer? If so try to boot from the cd. If this still doesn't work then that narrows down the problem a bit.

 

I can boot the windows disk no problem, as I said I cna get to the options of safe mode / sm with networking / sm with command / last known config / start normally etc.

It reboots after this.