Hi!

I attempted to restore the machine from the discs Compaq sent, and a
message immediately pops up saying they are the wrong discs.

Or they're not the "complete" discs. I remember that message showing up when
the computer was started from the "kicker" CD that Compaq sometimes handed
out in lieu of a "real" restoration CD.

What you need to reinstall Windows is an OEM-type XP CD. Any Windows XP CD
would work for this as long as it's an *OEM* disc. Yes, that would include
the Dell badged discs, so keep that in mind if you have one of those and the
version of XP matches (home for home, pro for pro).

William