Score, it was the hard drive.
That was the easy part. The hard part was getting an OS onto this thing that met all the family needs. For right now, I have Windows Vista for it. Through my work access to MSDN, I downloaded the Vista ISO, which proved critical in getting the same version as the version on the PC. The stickered Windows key didn't activate at first, but after calling the self-help robo-operator line, I was able to make the OS legit, so it's now running Windows.
The catch is that it's running Vista, and Jenny is looking relearning MS Office, the newest version of which requires Windows 7. You may intelligently ask, "can't you upgrade?" Sure, the upgrade cost is the same as a new license, $100. That sucks, no? The stupid thing is that buyiing a refurbed PC would get me the license for Windows 7 and the PC at the same time because OEMs don't have to pay $100 for a license.
As for parts, I scrounged up my old wireless card for my PC. It was a half-height card, so it fit in with no trouble. I did have to remove a bracket.
As for the hard drive, that came off my shelf. It's just been sitting around, being from the same era as the refurbished PC.
If Jenny chooses against it, I'll repurpose it to my daughter for $0 down. That's not a bad way to scrounge her up a PC.