Hold the phone for a sec.. What kind of PC is it?? HP/Compaq and other oem's partition your hdd and create a repair partition and that is just an image of your install hdd and you don't need an xp cd to reformat. Depending on the OEM it mainly is start, all programs, HP/Compac (or other oem name) tools and system recovery. Go into their tools and there should be an option to create an emergency recovery cd (it is just a boot cd that alows windows to access the repair partition. Did I make sence?? lol When you first turned the computer on it would have asked you to make a back up cd and (use dvd's of cource because it will be a disc image and about 10gb's). You should be able to still make a complete image file from their tool's folder. So be sure not to format like the rest of us do or you will lose it, and can be a pain to "Aquire" a copy that your key will work with.
- Edit - an easy way to tell if you do have a repair partition is in computer management you will see it,, also it will be there in the defragement screen.