People often find themselves locked out of their Windows 2000 or Windows NT systems as a result of a lost password for the Administrator account. Usually people consider the system a lost cause and start rebuilding it. However, you can use the following tip to work around this problem. When Win2K or NT boots, the OS usually displays the Ctrl+Alt+Del screen for approximately 20 minutes before the display changes and the logon box moves around the screen. When this happens, the machine has activated the screensaver logon.scr. If you replace this file with an alternative file (e.g., cmd.exe), the system will run this file under the system account instead of logon.scr. At this point, a user could issue a command such as Net User, usermgr.exe, or compmgmt.msc to reset the Administrator password.
Windows Privacy Tools - http//www.privacywindows.com