Recover from a registry delete?

OK, I've done it...got a little too happy with the delete key.
I was in HKEY_LOCAL_MACHINE and poking around the SOFTWARE field.
I was trying to delete a listing UNDER SOFTWARE but accidentally delete SOFTWARE itself. Now XP won't start...stays hung on the logo after the black screen logo, just before WELCOME. No safe mode, no command mode, no reboot with last known good configuration. And...system restore monitoring was turned off.
Does XP hide a backup copy of the registry that I can revert back to? And if so, how do I get to it?

 

You'll need to do a clean install. Anything less will not work. If you have data that you must save, there is a procedure for replacing the Software hive with the version found in the Repair folder. It's not a perfect fix but often allows for access for data backup.