Win XP repair failure, reboot looped! HELP!!!

I was trying to remove and reinstall Explorer in Win XP Pro Then rebooted and ran the Win XP repair function on the XP CD and while it is installing devices at about 33 - 34 sec it Reboots. I am locked out unless I perform a full reinstall. help please. can I Edit the command line that tells xp to run the install??? sys.ini ? boot.ini? command.com? not sure what it is? I followed microsofts directions for the procedure but was not sure on how to reinstall Explorer. since I did not actually remove it. I just told the Registry that it was not there.

boot to "last know good " and see if that helps....

I actually fixed the problem. xp install was crashing during Hardware Detection, so I physically removed all unnessary Hardware and Xp (Repair) install Completed.