Finally, by dint of the sort of focus that martial artists and practitioners of magic need to have, I managed to ease the screw loose, bit by bit. Turned out that some asshat had secured it with a dab of some form of screw glue. I cussed up a storm and put the hard drive in the clone body.
I did not plug the thing into wall current, thinking (probably wisely) that I should try it just on battery power lest something be wrong. (In retrospect, I should have tried it first with battery without HD, then with.) There was a massive failure to boot. I growled, glowered, and began the (much easier) process of putting everything back where I found it. V called just as I was finishing up screwing, and I told her the bad news.
She came over to pick the thing up and to get a few more things done while I was still around. It was finally time to go. I unplugged my spare green cat-5 cable from her new NIC, and something about the end of it caught my eye. "Hey, this thing has holes in it!" I discovered.
I looked closer. Yep, dozens of tiny little puncture marks. The sort not made by any machine. I started laughing and showed it to V.
"Looks like you've got about four cats left on that thing," she told me.
If eris_raven and I were still living together, that impertinent little fluff would get a severe glaring-at, and perhaps a bath. (shammash categorically does not chew cords or step on keyboards, because of bellow-induced trauma when he tried this as a kitten. Miss Raven was never so trained.)