The first step would be to check if your system has Windows XP drivers. If they are not available, you can still try to downgrade the operating system, but be prepared for some missing features or hardware support.After downloading the Windows XP drivers, simply get a licensed copy of the operating system and perform a fresh install on your PC. Then load up the drivers and you are good to go. Though it is technically possible to downgrade from Vista without performing a fresh install, and thereby saving your data files, we do not recommend it as some residue registry entries may result in system conflicts down the road.
As with all software installations, please ensure that you have backup your important data and read the necessary instructions before proceeding.