There are a lot of Windows password revealers and crackers available, but I’ve found that Windows Password Recovery Tool is the most effective.:
it not only supports XP, 2000, and NT, I have personally tested it with Vista Home Premium and Ultimate. It works perfectly to reset any local user account to a blank password
You can use the ISO to burn a boot CD. Follow these instructions:
1. Download ISO file from http://www.windowspasswordsrecovery.com
Windows Password Recovery Tool
2. Burn to a CD using a CD burning tool such as Nero or Roxio or MagicISO
3. Insert CD into drive and reboot.
4. You may have to select an option in the BIOS to get the computer to boot from the CD.
Booting up and clearing a password takes a minute or two works like a charm.