0X00000073
My desktop wouldn't boot into XP today. Kept getting a new blue screen (new to me, first time since switching to XP last year). Dell is shipping me a XP restore disc since apparently I lost the original, or they didn't include it with my desktop because it wasn't with the manual / others discs that came with my system. They are sending it overnight which is nice, I just wish that didn't mean Monday.
http://support.microsoft.com/default.aspx?scid=kb;EN-US;307545
If that is the correct code error that you are getting it does sound like a registry issue. Good luck and let me know if that helps.