Probably not if it's an HP...you will need to borrow/ not buy an official Windows XP CD that matches your version and Service Pack #'s....
I wish there was better news but it is what it is.
The only other alternative is to contact the manuf. and follow their instructions to do a Restore of your OS as it is probably on a hidden partition on the machine if you did not recieve CD's....
Unfortunately using this process will wipe ALL your data and any programs you have installed and take the machine back to Day One status.
This is why i suggested finding an XP CD as there are more alternatives that way...