|So the laptop starts but XP doesn't because you don't know the password?|
Start it up and before windows starts loading start tapping F8. A boot menu should come up. Choose one of the SAFE MODE options. On the user list that next shows there should be ADMINISTRATOR. See if you can start that as it's often not password protected. If it loads go into 'user accounts' in control panel and remove the password from the account you can't log on to.