In and out of sleep (no reboots) for over a week: instability, failures

Question

My wife rarely reboots her MacBook. She'll literally go a month without rebooting it. She just puts it to sleep when she's done and wakes it up again when she needs it. Only for the occasional software update will she begrudgingly and belatedly reboot the thing.
The same isn't true for my MacBook Pro. It takes about a week (or two at the outside) from the time I reboot my MBP until the time it manifests some kind of instability or soft hardware failure. Sometimes, apps crash, or I'll get a kernel panic (the gray screen that asks you, in multiple languages, to reboot). The last time, the computer wouldn't go to sleep when I closed it, and bluetooth became "unavailable". The time before that, the core keyboard and trackpad stopped working, so I had to use a USB mouse to cleanly shut everything down. A reboot always completely clears everything up.
I called AppleCare about this. They told me to run the hardware tests that come on the MacOS install disc. It ran for over 24 hours and could find no problems. Without some kind of diagnosis, they can't help me.
Both the MacBook and the MBP have had their memory upgraded. The MacBook now has one of the Apple (Samsung) 1GB sticks that had been in the MBP, along with another 1GB stick from Crucial. The MBP has one of the original 1GB sticks that came with the MBP, along with a 2GB stick from Crucial. My understanding is that in sleep mode, the memory is in a low power auto-refresh state (I get the impression that some of the peripherals are also not entirely switched off either). It seems to me that perhaps one of the memory sticks is bad. In fact, the 2GB one from Crucial I have is actually a replacement for the one I originally bought from them. Could I get two bad ones in a row? Is Crucial having quality problems?
I've decided I'm going to try each memory stick in isolation for two weeks with no reboots to see if I can tell which one is the culprit. (It's not going to be fun running with only the 1GB stick.)
There's one other thing to mention. These instability problems didn't always happen. They just started happening one day with two kernel panics in a row. Prior to that, I had been running some neural nets experiments, where I was running SSE-heavy code on both processors at full tilt for two weeks straight. I was concerned about the CPU temperature getting awfully high, so I installed a fan control tool to set the RPM to max, and I directed external fans at the computer. The problems started happening just after that. I'm concerned that some component(s) may have been damaged due to sustained excessive heat.
Can anyone give me any tips on resolving what's going on here?

Answer 1

Have you considered the possibility that the third party fan software might itself be implicated in the issue, theosib (or perhaps something else introduced at about that time?).
My inclination in a situation like this would be to back up your drive to an external, wipe the drive, and do a clean installation. At the very least I'd try an archive and install.
Do you have plenty of free space on the drive? Once you get things down below the last 10 to 20% things can get hairy at times, and may not be fixed as a result of simply freeing up some room, as free space fragmentation is likely to have set in.
As far as RAM goes, either "Rember" - http://www.kelleycomputing.net:16080/rember/ or, better still, but less user friendly, "memtest" - http://www.memtestosx.org/ does a much better job of checking your RAM than the AHT. Still takes a while to run for a thorough test, but much quicker than the approach you are planning on using.
You might also want to use "Activity Monitor" to check for any applications with progressive "memory leaks" or that are acting as CPU hogs, given your symptoms
Cheers
Rod