Update on the fan front: X31 no longer gives the “fan error” message, but has for some days now been refusing to start properly. When I turn it on, its screen stays dark, it emits a series of about ten irregular beeps, then does nothing more except whir a bit. It does not respond to anything. I turn it off, then on again, and the same thing happens four or five times until it starts up normally. I tried to do several things to it, and got good results blowing into it as described in the last post.
At one point I thought it might be a heat problem so I stuck it in the fridge for a few minutes (it worked great). An IT-literate friend (not the one from the last post) chided me about this: “moisture will KILL your computer”, he said;  so; no more fridge time.
I was too chicken to tell my friend that on hot days when X31 would heat up alarmingly, I would sometimes place it on top of an ice pack wrapped in a towel. I haven’t done this in a while, though, which leaves me wondering whether:

a)  The moisture has caused some damage resulting in this current spate of malfunctioning

or

b) X31 might actually have become ADDICTED to moisture due to icepack applications, and is now demanding the fix. “I know it’s bad for me”, it might be beeping to me, “but it’s just so *&%$ing awesome. C’mon, hit me again”.

or

c) It just likes my blow jobs.