Please post the Service Tag for the machine (on the outside of the case and can be soon in the BIOS (F2 when the computer is restarted and you see the Dell lofo).
Is this computer ruined?
Probably not
Is there something we can do with the disks and codes?
Use the disks to reload a new hard drive, if needed
If he purchased a new hard drive can he use his recovery disks on the new hard drive to install windows xp on his computer?
Yes
He purchased it used, is it too old to invest money in?
Not necessarily. If a hard drive fixes it and it meets his needs, he will be good to go.
You can download the free diagnostics from the appropriate drive maker's site to test that drive. If unsure, use SeaTools from
www.seagate.com The download will create a bootable floppy diskette that can run all of the diagnostics.