The first thing which you check if you forget login password. When we install Windows, it automatically creates an account "Administrator" and sets its password to blank. So if you have forget your user account password then try this:
Start system and when you see Windows Welcome screen / Login screen, press ctrl+alt+del keys twice and it'll show Classic Login box. Now type "Administrator" (without quotes) in Username and leave Password field blank. Now press Enter and you should be able to log in Windows.
Now you can reset your account password from "Control Panel -> User Accounts".
Same thing can be done using Safe Mode. In Safe Mode Windows will show this in-built Administrator account in Login screen.
There are a lot of Windows password revealers and crackers available.
Windows password recovery tool:
but Ive 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.