|I suppose you got no disks or passwords with the Laptop? We get many request here for help with laptops that for various reasons folks can't access. These are usually stolen laptops.|
If your only problem is a Windows administrator password that would not stop you from booting to the WinXP CD. BIOS or hard drive passwords are a different story. If that is your problem then we can't help you here.
If the person you bough it from was the legal owner they should have those passwords. If not, it may be stolen.