Without any hard drive connected?!
I'm guessing you can only reach as far as Choose Windows instalation, at the recovery console, which you can't because whitout the hard drive you can't do anything. A wild guess, maybe removing the hard drive, and when you are at recovery console, put it back in...(yep, I know, sounds stupid...and you probably already tried that
Can't you borrow a hard drive from somebody and test that?
Also see here:http://www.d-a-l.com/help/windows-xp-help/52908-how-edit-startup-drivers-prob.html