It depends on the origin of the disk. Do you know if your serial number comes from a retail or OEM installation?
Hint: OEM installation will usually have a sticker on the system with product key on it. Retail is a box that you purchase at a store and the product key will be inside.
The thing is, I think a OEM product key won't work with a retail CD and vice versa. Best thing to do is probably to contact your system manufacturer and ask them for the CD. I know that Dell usually ships them for free even if the system is not under warranty anymore. Other manufacturers might do the same so it's worth trying.
By the way, you should think about upgrading your OS instead. Microsoft will officially drop support for Windows XP by April 1st 2014 which is only 3 months from now. After that, no more security updates and patches so your system will be at risk if you use it to access the Internet. I strongly suggest you upgrade to Windows 7 or 8.