Now use a CD-RW or USB drive to extract any personal data files (My Documents et al).
Shut down the Toshiba and then reboot with a Win XP CD. Wipe the drive and reinstall Windows with the 25 digit license key you found with the keyfinder. Technically, there should be no need to reactivate but it may ask you to.
Reboot and setup the laptop as you normally would...finally restoring your data files.
Then look into a nice imaging software like Macrium Reflect. It's free and will make an image of your hard drive while Windows is running. It's sweet and will allow you to restore an image should this happen to you again...thereby negating the need to wipe and reinstall WinXP. Just re-image.