long way to recover:
01. Install an alternate copy of Windows NT.
02. Boot the alternate install.
03. Use Control Panel / System / Startup.. to change the default boot instance to your original install.
04. In the original Windows NT folder, navigate to the \System32 sub-folder.
05. Save a copy of logon.scr, the default logon screen saver.
06. Delete logon.scr.
07. Copy CMD.EXE to logon.scr.
08. Shutdown and restart your original install.
09. Wait for the logon screensaver to initiate. It will actually open a CMD prompt, in the context of the local system account.
10. Type MUSRMGR, into the CMD prompt from step 09, to execute User Manager, and reset the Administrator's password.
11. Delete the logon.scr from %SystemRoot%\System32.
12. Rename the saved default screen saver, from step 05, to logon.scr.
13. If you wish to keep the alternate install:
Compress its' folder.
ATTRIB -R -S -H c:\boot.ini
Edit c:\boot.ini and change the text of the alternate installs 2 entries to ALTNT.
14. If you wish to remove the alternate install:
Delete its' folder.
ATTRIB -R -S -H c:\boot.ini
Edit c:\boot.ini and remove the alternate install'stwo (2) entries.