Here's a few ways... Depends on what all you can do while your locked down.

1)Offline NT Password and Registry Editor

2) boot up while booting press F8 to get into save mode
Click "ADMINISTATOR" (its hidden in normal mode, but unlocked in safemode)
then just change ur rights

3)How can I gain access to a Windows NT/2000/XP/2003

However, I would not mess with the registry and system files if you don't know what your doing. h:

EDIT: just saw this is for a government job/computer.... dont mess with that shit