I installed Vista on a laptop that was little used at the time and now want to go back to XP. The laptop is now in regular use and we are having trouble getting it to work amiably with the other computers in the house, both of which are running XP. There doesn't seem to be anything built into Vista that will let you revert to XP, which it was running before. I tried booting from an XP Pro installation CD but the setup program was blocked by Vista. I even tried formatting the laptop's C: drive. No luck.

Is there any way to do this?