After a bit of poking around in all the usual places (eBay, Craigslist, Google in general), I found a computer for sale on the other side of the Bay which had a motherboard identical to mine. The Craigslist ad for it was a bit over a week old and the price low enough that I figured it had already sold, but I sent off an email to ask anyway. It turned out that the computer was still available after all, and so Saturday afternoon tiger_spot
and I drove over and I bought it.
With rather a bit of fiddling, I transferred the new motherboard into my computer, and it seems to be working. There was an stressful incident where it crashed five minutes after I'd first started using it (just long enough to get my programs open again!), but I am pretty sure that was a heat-sink problem, and now that I've adjusted the heat sink it seems to be working fine for the last day or so.
(And thanks muchly to those of you who offered loans or gifts of spare computer stuff in response to the post about it having crashed -- it was very comforting to have options other than "buy a new one", even if I didn't end up taking you all up on any of the offers.)
In other news, when we stopped to drop off tiger_spot
on the way home from mikz
's Projects Afternoon yesterday, and temporarily parked Suzi's car in a not-really-a-parking-spot, it wouldn't start back due to a dead battery....