I'm not sure, but I think DarkElite may be talking about a startup password in the BIOS, which would pretty much prevent him from getting on at all unless he cleared the BIOS with a jumper, but then that would of course erase the password, and his parents would know. If it is in fact just a Windows password, you could boot in safe mode as KSNiloc said, create an additional user/password. That way the old password would still be there, but you use the new one to get around it. Of course this won't work well if your using WinXP and the users are displayed as icons.