Maybe, it depends on whether or not there are drivers for the hardware on your system for XP. Most systems sold within the last 3 years, give or take, cannot run XP. However, there are literally dozens, if not hundreds, of posts on just these forums alone that describe the general process. Expanded to the greater Internet, and we're talking thousands, tens of thousands, possibly up to millions, of posts on the subject. So, I'm sure pretty much any question you might possibly have will been answered already, you just need to do some reading.
Window7 won't let me downgrade to XP