Admin locked out. Password will not work. Help?

The other day I tried to log in to my computer, but it told me I'm locked out. The problem is that I can't access the other admin account because I don't have the password. I know the lock out occurred due to someone attempting to log on, and failing to enter the right password. I can't access anything from the log on page. I also tried CTRL+ALT+DEL twice really fast, but nothing happens. I tried scouring the net, but all I can find are posts on how to recover lost passwords, not fix lock outs. I have XP pro, and I can provide further information if necessary. Assistance would be appreciated. Thank you