The easiest way to reformat I found is either use a different computer and format the drive that windows XP is on but dont forget to set the jumpers to slave on the HD. You could also partition the drive into three different partitions, put one OS on a differnet partition, then format the old OS, then reload a new OS on the newly formatted partition. Finally wipe the dummy OS you used for reloading the OS. This is a longer process and could take much of your day but it works if you dont have a different computer to hook the HD up to.