So I'm trying to diagnose my machine. I started getting random bluescreens a while back, and I assumed it was a RAM problem based on the random nature of the occurrence, and whatever the error message was. I confirmed this by running a memory test and getting a buttload of errors. Oddly, I also noted that any time I unseated an re-seated the RAM, the problems (and the errors) would go away for about a day. Anyway, I bought new RAM, and called it a day. A few days after I replaced the RAM, I started getting hard lockups. No bluescreen, the screen would just freeze (and whatever sound had been playing would have the last quarter-second repeated indefinitely). I thought, "well fuck, if it wasn't a RAM problem, the motherboard must be toast. What else would produce RAM errors?" So I replaced the motherboard. The (new) RAM in the new motherboard tests A-OK hunky-dory in memtest86, but the lockups are still happening. Processor? Video card? HD seems to be fine. Machine runs just fine most of the time (until it locks up). I can't think of how I can test those components individually without replacing them, and the cost of doing that is going to get really annoying really fast. I tried running a surface-test on the HD, just to confirm, but the machine inevitably locks up before it can finish (though I never saw any errors on the test). I also have a spare processor/mobo/vid-card combo, but none of the old shit is interchangeable. I could swap the whole shebang out and see if it works, but I suppose it would only confirm that it's not the hard drive, and I'm getting sick of swapping out motherboards. Anyone have any bright ideas?