I honestly don't know the costs. I did do some research on the HP/Compac site concerning your model of computer. It may be possible that you can order a set of recovery disks from HP...OR...there are instructions on how to make your own. Let me check with somebody a bit more knowledgable in this area and I will get back to you on that. But for now......
......here are the instructions given on THAT site, and it makes NO mention of using the disk...unless you have XP SP2 installed and then it says to reinstall SP2 but otherwise these are the instructions given in total;
To repair SP1 or earlier XP PCs, click Start , and then Run . Type sfc /scannow into the open field, click OK , and wait until finished.
No mention anywhere on the page about inserting your Windows XP disk at all...so try it and see what happens.