Hi eddkot . Try doing what I'm about to tell you,but I'm not going to give you a long detail of every thing though. I remember when I wanted to remove vista from my pc & try putting on another previous operating system. What I done was to put the original retail boxed DVD into the DVD burner & go through the motions,but click the format button to format your entire hard drive disk. This worked for me,but I do not know if it will work for you. One more thing though make sure that you can go to your windows 7 operating system disk through the start up into bios rather than going into the fully booted windows 7 operating system. Now if this works,than you should be able to reinstall or install windows XP onto your hard drive disk within your pc. Do not forget to hang around though so you can stop reinstallation after having formatted your entire hard drive disk as you will not want the motions of reinstalling your windows 7 operating system onto your pc.