You can take it to somewhere like BestBuy and they can format it for you. Also if you have the OS disc you can use it to format the hard drive. Just put in the disc Choose Boot from disc in the BIOS and it should start the installation, it should ask you what hard drive you want to install on, click the hard drive that is messed up and then click format. This is how i did it on vista it should be pretty similar on XP. If that doesnt work you can google how to format hard drive on XP.