You could have a look on bit torrent sites for a copy of XP. Once you've got your XP disc, go into your bios whilst booting your laptop and change the boot priority to CD/DVD (from disc). Should give you a fresh install. Might be worth formatting the HDD during the process just to make sure you get rid of that pesky Vista.Once its completed make sure you change the bios setting back to booting from HDD. You should know that there's not going to be support for XP for much longer via security updates, so bare that in mind also.