Sorry, I should have stated, I already did basic troubleshooting.
However, I ran through it again tonight. Here are the results:
Test 1: same config as last night. Boots, no errors reported, diagnostic lights green across the board. Keyboard/mouse don't work, even when swapped out for known-good ones. Windows appears to have hung. Network link light lit, activity light not even flickering (though it should be, because I'm trying to ping it from the router via the laptop I'm on now and the remote admin console on the router). Forced to go for hard shutdown via power switch.
Test 2: system hangs during POST, diag lights state "Other failure has occurred", no message on the screen. Shutdown via power switch.
Test 3: system hangs during POST, beep code 1-3-2, memory error. Shutdown via power switch.
Test 4: system hangs during POST, CPU fan (normally all-but-silent) cycles up to JET ENGINE AFTERBURNER levels, vibrating entire case. Power light solid orange, diagnostic lights aren't lit. Power switch nonresponsive, have to kill it by yanking the cord.
Test 5: system boots to Dell tech support advertisement screen, though diag lights report no error. Tech sup screen says previous boot failed at checkpoint [WAKE] and to contact Dell support. Shutdown via power switch.
Test 6: system boots to Windows, mouse moves for a quarter second before system hangs. Shut down via power switch.
All of this (except the JET TURBINE) could be attributed to memory error -- and that beep code is suggestive, I'll admit -- but removing either stick makes no difference. Tests 7 - 10 display the same results, ie, the system saying "DURR I AM BROKED" in a variety of ways. I have 2 1GB sticks, swapping sticks and slots for those tests, with no obvious pattern emerging..
Searching for the symptoms I'm getting via Google suggests a bad capacitor (or several) on the motherboard, and sure enough, when I kill all ambient noise and stick my head in the case, I can hear the tell-tale high-pitched whine of a leaky cap. It's not blown, yet, but it's fluttering. It could be the PSU, causing random over/undervolts on the power lines, or it could be the mobo, since the bad cap issue is a known problem with Dell GX280 systems.
If you have any suggestions, let me know. I'd much rather just fix the bitch than replace it and go to the hassle of reinstalling and so on and so forth. I've been trying to identify if the PSU is bog-standard ATX or if it's some proprietary Dell crap and not having much luck. If it's the former, I can test the "bad PSU" theory easily enough.
--sofaspud
--
"Listening to your kid is the audio equivalent of a Salvador Dali painting, Spud." --OpMegs