This evening I was cleaning. I cleaned my spare 3" disk drive. Using isopropyl alcohol and cotton buds I scrubbed away all the old drive belt rubber from the pulleys, and then I fitted the replacement drive belt. I haven't tested it out yet. I should have taken photos, but as I've done this before it didn't seem like something which needed documenting.

After that, I took my PC apart and took all the RAM sticks out and re-seated them, and then disconnected and reconnected all the drives and power, and then squirted compressed air all over the place. Now I'm coughing from all the dust, but hopefully my PC will now stop segfaulting all the time, and I'll stop wanting to throw it out of the window.

Everything else I wanted to do was dependent on getting some more bits and pieces first.