I've been gathering information about reinstallation myself as I'm getting ready to change my hard-drive.
Dell has been installing a recovery partition since at least 2004. Check to see if you have one. If you do have one, you could use it to reinstall your system. The computer would be back to the way it was when you bought it.
If you want to use the disks, then I don't think you should create partitions as I think this would remove the recovery partition. I'm not sure of that though not having done it.
Here is a link to reinstalling the drivers for your computer: http://support.dell.com/support/topics/glo...mp;doclang=en#1
Here is Dell's guide to restoring Windows with the Recovery partition: http://support.dell.com/support/topics/glo...mp;docid=336966
Here is Dell's guide to reinstalling the OS: http://support.dell.com/support/topics/glo...mp;docid=339949
If you can't boot to the CD, then here is the guide to how to begin the setup program: http://support.dell.com/support/topics/glo...lang=en&cs=
Here is a link to a site that fills in some of the blanks that DELL left out (Thank you Maurice Naggar) http://www.winsupersite.com/showcase/windowsxp_sg_clean.asp
When you ordered your computer, did you have them send the reinstallation disks? If not, you should contact Dell to get them. You should use the DELL reinstallation disk for the OS as it is keyed to the BIOS (thanks ddeerrf) and because there are special codes that DELL entered that would be eliminated if you used a retail XP installation disc. Using the latter would create problems when re-authenticating your system. You should also have discs containing the drivers and the other software that was installed on the machine when you bought it.
Note: I'm editing your title to "reinstalling windows". That is rather different from "programming" and fits your question much better.
Orange Blossom Edit to add answer to this question:
So there's no point where you have to put a registration key code thing
If you reinstall windows, you have to enter the product key which is used for reactivation purposes. That number should be on the side of your disk tower if you have a desktop. Not sure where it is on a laptop. If you use the recovery partition, the key is already entered. However, you still need to reactivate windows.
Edited by Orange Blossom, 04 June 2009 - 12:06 AM.
Correct one link and add another for system recovery. ~ OB