Powerup password don't know bought at yard sale

Power up your 'puter and press f8 to enter windows in safe mode.When it boots into safe mode go to your start button... select control panel.. and find user accounts . Enter and make yourself a new user account.. select administrator account . Close and and reboot the computer. Select your new user account and it should boot into windows. Go back to user accounts and you should see your account.. a guest account.. and the account of whoever owned the computer before you . That account will say password protected. select delete user account and click on the old users account . Windows will say it will delete the account and all files of the user. if it asks select ok and be patient . It will be a few minutes as windows deletes the account. Do a final reboot and the old account and password should be gone.
Good luck.
Don