Windows XP/2000 - windows pass word on start up posted in the Operating Systems forums; My father recently changed his windows pass word (on start up) how do you recover or change. (windows xp)...
It could be that the administrator account is not passworded so i suggest trying this first. Boot the computer and when it gets to the welcome screen press ctrl-alt-del twice to bring up a log on box, then type in Administrator as the username and leave the password box blank.
Then go on Control Panel > User Accounts and choose a new password.