Since Hp doesn't list XP drivers for that model, you will will have to search for XP drivers for each hardware device listed in device manager. You will need to find sound, video, network, chipset, modem and possibly others. Do a google search on each item to see if you can find XP drivers for it, you may get lucky. What I would do is get a extra drive and try installing XP before you screw up your Vista installation.