To reset your password in Windows Vista, access the System Recovery Options screen after booting the operating system from the Windows Vista install disc and use the Command Prompt to input a new password for your account. Once the process is complete, eject the disc and restart your computer.
Access the BIOS screen, and make sure that Windows Vista is configured to boot from the optical drive instead of the hard drive. Insert the Windows Vista install disc, and restart your computer. When prompted, select the Repair Your Computer option, and write down the drive letter indicated in the Location column. Once the list of installed operating systems appears, select Windows Vista, click Next, and select the Command Prompt option in the System Recovery Options screen.
After the Command Prompt activates, type ”copy c:windowssystem32utilman.exe c:”, and press Enter. After that, type “copy c:windowssystem32cmd.exe c:windowssystem32utilman.exe”, press Enter, and select Yes when the overwrite prompt appears. If you installed Windows Vista in a location other than the default one, replace the C: part of the commands listed above with the drive letter you wrote down earlier. Eject the Windows Vista install disc, restart your computer, and select the pie-shaped icon on the login screen. Type “net user” in the Command Prompt, add your username and a new password to that command, and press Enter. This should allow you to log in with the new password.