No Beep. PC Coma.

[xyzzy@bok]

My pc froze and screen black. Unplugged, plug back in, press start; No Post beep, black screen [signal going to monitor but no actual text or anything] basically a dead machine right? not quite but almost certain by the time i've stripped it right down, drives off, cards off, ram out, cmos battery out, bios jumper used, cpu out and reseated, powersupply off, open power supply, find no obvious problems. what more can i do? reassemble everything, power on --- no beep. Go away, walk my dog, 2 hours later try pc.. perfect post, beep etc. cmos checksum error but to be expected, loaded optimised defaults, restart perfect; XP desktop all ok - Lazarus. What is going on here? This scenario happened before, 3 months ago. I got theory ideas but , what is going on here? Your ideas welcome but i give no more clues to this pc riddle, don't want to influence your diagnosis. :-)

[j2buttonsw]

My guess is the power supply. They can look OK and power up cpu fans etc etc but do not power the mainboard sufficiently. They can also go "dead" only to spring to life again as you describe (there is an internal cut off switch, that can be activated by shorting the 12 or 5 V lines, which can reset itself). The PSU is often the first thing to go on a PC so I would think about changing it (my guess is that your problem will recur more frequently if left).

[darth vader]

pixies. they're a blooming nuisance and difficult to remove without resorting to gas or magic dust

[LeMarchand]

I have had a similar problem. If blow the dust off the internal componets, it seems to cure it. I'd be interested to know if anyone knows what the cause is, though.

[xyzzy@bok]

thx J2 and LeMarchand, both good answers; i finally found a bit of fried fluff on the mobo. was this the demon. anyway so far one spotless pc and 30 hours later, still running great. So pixie Schmixie, Darth, unless you count dust bunnies. :-)

[bobbydazzler]

Some good advice here...and dust is both conductive and heat retaining so its a good idea to occasionally blow out the innards of your PC with one of those cans of compressed air....but a word of warning good folks....disassembling PSU's aint a good idea due to the presence of capacitors. They can give off a hefty, if not fatal, clout even hours after removing power!