Available solutions:
1. Login as administrator to reset password for other password (boot computer on safe mode).
2. Reset windows password with password reset disk.
3. Reset windows password with password tools.
4. Reset windows password with install cd.
More inforamtion:
1.
Use windows password reset disk
If you forget your password, you can reset it using a password reset disk for your user account (or the password reset information stored on another type of removable media, such as a USB flash drive). If you don't have a password reset
disk, you'll need to get someone with an administrator account on the computer to reset your password for you.
1.
If you enter the wrong password when you attempt to log on, Windows displays a message that the password is incorrect. Click OK to close the message.
2.
Click Reset password, and then insert your windows password reset disk (or other removable media).
3.
Follow the steps in the Password Reset Wizard to create a new password.
4.
Log on with the new password. If you forget your password again, you can use the same password reset disk. You don't need to make a new one.
http://windows.microsoft.com/en-US/windows-vista/What-to-do-if-you-forget-your-Windows-password
2.
Reset or recover password with Spower windows password reset tool
2.1
Download and install spower windows password reset tool.
2.2
Create an usb or cd password reset disk.
2.3
Boot computer from password reset disk.
2.4
Reset computer password with password reset disk.
http://www.windowspasswordsreset.com/windows-password-reset-guide/
3.
Reset windows password with chntpw
3.1 Create a chntpw usb or cd bootable disk
3.2 Boot your computer from chntpw bootable disk
3.3 Follow the instructions step by step to
reset windows password on DOS console.
Hack Windows xp password with Chntpw
4. Reset Windows password with install cd.
See http://social.microsoft.com/Forums/en-US/studentrockstar/thread/bd195503-06ab-47a7-b941-f5fe2c2215bb