Weird computer behavior

[ober]

So I was playing HL2 CTF and everything was great. I stopped the game and went into the kitchen for about 45 minutes. I come back into my office to find my PC not really responding to mouse movement or keyboard presses. The power light was on, but no HD activity.

I figure something strange must have happened so I just hit the reset button. Nothing. I held the power button until the power light went off and then tried to start it again. Nothing. Well, I shouldn't say "nothing". The power light came on and the power indicator light on the mobo came on. But nothing else was going on. No beep codes, no video, no POST, no HD activity.

So I unplug, plug back in, try the power button a few more times, but nothing. I figure it must be the PSU, but then I give it one last try, holding in the power button an extra second for good luck, and it booted right back up like nothing happened. It's working fine now, but I'm wondering WTF went wrong?

Any ideas?

[Thantos]

I would guess the computer was tired of you getting owned by HL2

Did you give it time to dissipate the capacitors prior to rebooting? I have found that giving it a full minute for everything to settle down (like the HD spinning) can affect the reboot when things get weird.

[ober]

Ok, I'm starting to think I have some kind of virus. It shut down randomly on me the last time I had it up. I hope I can keep it up when I reboot long enough to install Norton.

[ober]

Crap... now it won't boot at all. The processor fan kicks, the mobo light is on, and the power light on the case stays on. But it doesn't do anything past that. I'm beginning to think power supply, possibly motherboard.

This sucks.

[no-one]

uh... random reboot doesnt mean ........... norton is not even close to a guarantee its not a virus...
is it over heating or something? or if your PSU is ruined then that could feasibly cause random powerloss? could be mobo or anythin... furthermore i demand you do more diagnostics work.

edit:... late post... well its probably mobo or power then..

[InvariantLoop]

Just a suggestion, check your power button. it might have gotten loose and out of place so it doesnt make good contact. when i build my pc i had a similiar issue, when i had the tower laying down on the floor it would power up, but as soon as i put it upwards it would power up for like 5 secs and then shut down, after many trys i finally saw the power button had gotten loose.

[SpudNuts]

I would disconnect everything from the mobo, all drives, expansion cards, all cable that arn't necessary (of course you'll need to keep the power switch connected, but as posted above, make sure it's secure). Just leave a stick of ram, CPU, fan, video (if not integrated) and see if it posts. If it does, connect one item at a time till you get to your problem. If it doesn't, you've narrowed it down to ram, CPU, mobo, PSU. Replace each one with known goods until it works, start with the easiest, CPU, RAM, then go with PSU and lastly the mobo.

[ober]

Ok, just to give you all more details:

The PC and all components are less than 2 months old. I built the PC myself and it has been working fine ever since (except for the fact that one of my RAM chips came DOA, but I've had that replaced). I don't think the power button is loose, as I have not been in the case or bumped it recently, although I will double check that. However, that would not cause a random shutdown, because when the system is powered on, you have to hold the button for 4 seconds for it to shut down.

Everything is pointing to the PSU, which I got at a bargain (should have known it was too good to be true). I will put a different PSU in it tomorrow and see if that fixes it. If it doesn't, I'll be looking for a new motherboard. At least I have my wife's computer to play with.

Keep the suggestions coming!

[no-one]

your bald arn't you?

[major_small]

I would disconnect everything from the mobo, all drives, expansion cards, all cable that arn't necessary (of course you'll need to keep the power switch connected, but as posted above, make sure it's secure). Just leave a stick of ram, CPU, fan, video (if not integrated) and see if it posts. If it does, connect one item at a time till you get to your problem. If it doesn't, you've narrowed it down to ram, CPU, mobo, PSU. Replace each one with known goods until it works, start with the easiest, CPU, RAM, then go with PSU and lastly the mobo.

I would suggest something similar, but not the same. when I had similar problems, I disconnected both my 2nd HD, both CD drives, and two fans and it started fine. then I reattatched (sp?) my other HD, and all was fine. then I connected another CD drive, and still everything was ok. then when I attatched my last CD drive, I noticed it always stopped booting when it tried to spin the CD drives.

the FIRST thing I figured was my PSU, so I checked voltages without the CD-Drives, extra HD, and 2 fans, and it was all fine. then I reconnected my CD drives and HD, and tried again. as usual, the system powered up, and then powered down. I then measured the voltage and saw that my system was horrifically underpowered. a new, more powerful PSU solved all those problems.

I would definately NOT start with the CPU - that's one expensive piece of equipment to replace as a first try... I would also rule this out as a RAM problem... I would also not worry about removing extra cabling, seeing as not much power goes through the cables if the drives are not connected to the PSU.

The processor fan kicks, the mobo light is on, and the power light on the case stays on. But it doesn't do anything past that.

this is exactly what happened to me. like I suggested, when it gets to this point, measure the voltage comming out of the PSU. I'm willing to bet it's dangerously low.

also, the fact that you said all the parts are ~2 months old, that leads me to believe that you were overtaxing your PSU and it finally crapped out... my second CD drive worked perfectly fine in my system for about 1.5 months, when the system started freezing, i would get intermittent booting problems, etc. then it escalated into just not starting up.

hearing your system power up and lose it's juice is a little bit sickening sometimes...

[RoD]

sounds like overheating to me. I know its an AMD. Take your proc fan off, and the cpu out. Wipe the core off really well, as well as the HS, get dust off fan, etc. Take some 400 grit sand paper, wet it, and lay it on a level surface, Lay the HS flat against the sandpaper and go 20 times clockwise and 20 times counter clockwise in a oblong circular motiuon, basically a oval. Wipe HS off, do it one more time. Put some new compound on it and get a good seat between the HS and fan and the chips core. Try now.

[ober]

Actually, it's not an AMD. I wish it was, but I got too good of a deal on a P4 to pass it up. And it's not overheating, I've been monitoring that on and off since I've built it.

It ended up being the PSU. I put a new, heavy duty PSU in this morning when I got to work and it boots up like a charm with everything connected. I guess that's what I get for buying a cheap 550W PSU. I now have an industrial 510W (true wattage) power supply. Now I just have to worry about replacing it.

Anyways, thanks for all your help, especially major_small. I figured that was my problem, and your description backed up my hypothesis.

[RoD]

Damn i could have sworn you build an amd : )

Glad you got it fixed, i seem to be off this week hehe.

[ober]

That was my origional plan, but a friend of mine had a combo deal that he offered to me and I couldn't pass it up. My previous build was and AMD, however.

[RoD]

Must be where i got it from lol