1. insert OS disc
2. go into BIOS and make the optical drive the 1st boot device
3. restart
4. press any key when prompted
5. follow format/install process
How much RAM is in your system? I would suggest at least 1G if your going to run XP. Before you format your system, check out the manufacturer's website to see if they have driver support for xp, as you'll have to reinstall the drivers after the install.