Hello candysdaddy09,
If your computer was manufactured by a large company (Dell, HP, Gateway, so on) and the computer came pre-installed with Windows, the computer would have come with OEM Reinstall or Restore (to Factory condition) software. The software usually comes on a disk that came with the computer, or it may have been included on a hidden partition on the computer's hard drive. Please review the documentation that came with the computer or contact the computer's manufacturer for assistance in finding/using the software. The Manufacturer may also be able to provided replacement software, if you have lost the disk.
If you install XP, on the computer, after you bought it (or built it) then you will need to find the disk that you originally installed from. During install, use the Product Key that was included with the install disk.
If you need technical assistance on how to go about reinstalling XP, please post your questions in one of the XP Newgroups at
http://www.microsoft.com/windowsxp/expertzone/newsgroups/reader.mspxThank you,
Darin MS