You should first check acer's website to see if it has drivers for windows xp. If you format, you may need to install the sata driver with a floppy, which almost no newer systems have. I had no problems with xp pro finding my sata drive, but it comes with service pack 2, which regular xp may not have. I suggest if you use regular xp, order service pack 2 from microsoft or search for it on craigslist if you have one in your region. The one device driver you must find which xp won't include is the lan port driver; if acer doesn't have it for xp, use everest or some other free download to identify the lan driver and do a search for it before formatting your hardrive. If you can't burn this driver to a cd, I wouldn't try installing xp. With the lan driver, you can go online and let windows search for other device drivers. Without it, you may have problems.