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My PC malfunctions in very unusual way, please let me know if anyone seen something like that before.

When turned off and allowed to completely cool down (not something that done on regular basis) PC takes up to 5 minutes to warm up in order to post. You turn it on and nothing happens, it ether fails to post or if it does goes into ntoskernl.exe error. After few minutes of letting it sit turned on (cycling reset seems to speed it up) it cures itself and works 100% fine and passes all stability tests with flying colors. Follow up reboots go without problems.

I'm thinking some capacitor in motherboard is failing and it will need to be replaced. Any more ideas? Thanks.

Unplug some stuff you don't need to boot (DVD drives, extra hard drives, etc.) and see what happens.

My old PC used to do that. It does sound like a motherboard problem with, as you suggest, a capacitor issue. There's no fixing it beyond getting a new motherboard.

If it's a leaking aqueous capacitor and you can spot which ones, it can be replaced with a fairly difficult solder job. Easier just to replace though. Could be power supply, but I kinda doubt it.

Perhaps it's just time to upgrade.

Might be a heat issue, contacts separate when cool and connect when hot.  Still, get a new board or don't power down.  Computers generally break when powered down, so don't do it.  I've seen machines that were running solidly for years that would not even spin up their fans after a powerdown.

We're talking about POSTing here, so it has to do with the power supply, CPU, memory, or MOBO right?

My money's on the power supply, see if you can swap it out with another one laying around.

Depends on what part of the POST. If its not starting to POST at all, then ya, I'd say ya, MOBO or CPU on the fritz. If its getting past the very initial part, but hanging thereafter, it could be an IDE drive that's clogging the post process. This happened to me lately when I pulled out a primary slave drive but didn't change the jumpers on the remaining primary master. It hung looking for that primary slave till I pulled the primary master and set it to cable select instead of primary master w/ slave.

Power supplies and RAM problems can look like any thing and everything. If this is as repeatable as you are saying. I would have to agree it is sounding like a motherboard problem. Some very good advice has been given. Unplug and disconnect every thing not needed to post or boot. If the problem does not change than the parts needed to post or boot have the problem. Start swapping out what you can. Eye ball the cappastors on the motherboard, If they have goo oozing out that capacitor has changed value and is potentially the problem (or part of it)

I think for now I will stop turning off my PC.

try not to burn the house down. 


seriously if you are having what may be an electrical issue leaving the faulty component on may be a costly fix.

He's correct.  I hate it, but I turn mine off when I'm not home.

A co-worker of mine had a machine that caught fire, in a big way, but he was fortunately home at the time.

This is really only true for gaming machines that have modifications, big-ass power supplies, fancy cooling systems - basically a dozen more things to go wrong than a typical workstation.  An out-of-the-box machine doesn't have nearly the same level of sophistication, and can usually be left running for their entire lifespan with no worries.  The fewer moving parts, the safer the machine.

But, yes, a machine will definitely last longer if it is left on.  Less expanding and contracting of components and connections, etc.

I have an entire C-grade semester of electrical engineering under my belt, so I am in no way qualified to offer my opinion:

This is a capacitor.  Either the mobo or the psu.  One needs to be replaced.

A cap may have popped it's top but if it was completely a goner he would have smelt it long ago (he should eyeball the caps in the psu and on the board for rounded or cracked tops).  As stated it could also very well be a loose solder joint (or a million other things) either way I would swap out the psu 1st to see if that fixes the problem.  Too bad he doesn't have a post meter to see what codes it is giving out.

Sadly swapping PSU is not an option... It is 700w  and I need 450w of it to just start my PC. PSU will shut down if critical temperature reached, for example as a result of fire, and insurance and fire alarm will pick it up from there.

Unplug all your harddrives... try and boot to your windows CD from your DVD/CD rom. Let us know if that allows it to post normally. I betcha this is the harddrive, or the SATA/IDE controller. Or maybe even the cable.