HELP!! PC powering off randomly, at random times, for no reason!

[fishsponge]

Hello...

My computer keeps powering off for no apparent reason whatsoever, it seems. This obviously isn't the case, but i don't know what the reason is.

Anyway... here are my symptoms...

• There are actually 2 issues i'm experiencing... 1. The machine instantly powers off, without warning, and with no errors or beeps. It then powers on again fine, once i've taken the power lead out and put it back in again. 2. The monitor goes black, and loses the signal from the graphics card, but the fans continue to run, and everything is powered up. I then have to manually power it down, and restart it.
  
• Sometimes runs faultlessly for hours and hours.
• Sometimes runs for about 5-10 minutes and then shuts down.
  
• Temperatures are fine: CPU - 50 C, Case - 39 C.
  
• 1 week ago, it powered off at 2:30pm while i was at work, on a really hot day, and wouldn't power up again. I got brand new 400W PSU. The only items plugged into PSU are motherboard, HDD, FDD and 48x CD-RW and one case fan.
  
• It runs perfectly for as long as it wants as long as i don't use it.
  
• I use up 100% of idle processor time with DNET, so CPU usage isn't an issue.
  
• It does seem to poweroff more when i'm using graphics intensive executables (Colin McRae Rally 2.0, Driver etc...). Occasionally though (about 10-15% of the time) it simply loses the signal from the graphics card instead though.
  

So... my conclusion is that this problem is not related to temperature, power consumption, PSU faults, cable problems or wall socket polarity (i'm in the UK).

I'm tempted towards saying it's a graphics card issue, but the same graphics card, with the same motherboard, with the same PSU, same HDD, same CD-RW, same sound card, same USB card and devices, same mouse, same keyboard, same case, same monitor, same drivers and operating system installation have all worked together *perfectly* since Christmas!!

Any ideas people?? i'm really confused, and this is getting to be a bit of a pain, lol

thanks in advance

[Eraserhead]

Could be a graphics card problem. Try using a different card if you can get hold of one, see if it makes any difference

[vanik]

Ugh I have the EXACT same problem.. its on my thread in the main page too

Just to offer some insight, I had a nvidia TNT and changed it to a geforce fx and it still had the same problem.. it might not be the gfx card

[nurdonsite2]

did this just suddenly started to happen? or did u install some new hardware or made some other physical change to the machine before this started to happen?

[Omardeth]

to me this sounds like classic power supply going out . random reboots are either a heat issue or power supply dieing most of the time . if you can try replacing the power supply . i would recomend a 400w or better . but this sound like the power supply is going . you said it will be fine but you noticed that if you do something that the grafic card is being used with it will reboot . well when the grafic card goes to do 3d it will pull more power than 2d . boom it reboots .

question when wa sthe last time you blow out the case with caned air ? dust build up can make the power supply work harder than it would normaly and also it holds heat in .

hope this helps

[pickel]

Make sure you have a good ground at the power receptical. Also check for a loose neutral wire. Intermittant power surges can cause all kinds of funny things.

[fishsponge]

Originally posted by Eraserhead
Could be a graphics card problem. Try using a different card if you can get hold of one, see if it makes any difference

as you can see though, i have had the *exact* same hardware configuration since Christmas, with the exception of the PSU that broke 2 weeks ago. Also, vanik is having this exact same problem, and he's already tried replacing the graphics card.

Originally posted by nurdonsite2
did this just suddenly started to happen? or did u install some new hardware or made some other physical change to the machine before this started to happen?

ok... what happened was this... My machine was running perfectly without a problem or a care in the world since Christmas, until a really hot day last week. The PSU broke at 2:30pm on this hot day, so i got a replacement (as it's under warranty). I fitted the new PSU, and now these issues are occuring. that's all i've changed.

Originally posted by Omardeth
to me this sounds like classic power supply going out . random reboots are either a heat issue or power supply dieing most of the time . if you can try replacing the power supply . i would recomend a 400w or better.

ah... but it's a brand new PSU. it's 400W as well.

Originally posted by Omardeth
...but this sound like the power supply is going . you said it will be fine but you noticed that if you do something that the grafic card is being used with it will reboot . well when the grafic card goes to do 3d it will pull more power than 2d . boom it reboots .

true... but it's a 400W PSU that i currently have in there (i also had a 400W one before it broke). I hardly have anything plugged into the PSU, so why should it be pulling too much power?

Originally posted by Omardeth
question when wa sthe last time you blow out the case with caned air ? dust build up can make the power supply work harder than it would normaly and also it holds heat in .

in my original post, i said it's a brand new PSU, so there's no dust whatsoever. none inside the case either.

strange problem eh??

[Omardeth]

i still think it is a power supply problem . because the supply says it is 400W doesn't really mean anything . it can be a 400w power supply that only puts out 11A on the +12 volt rail . if this is the case it is under powered . look on the side of the power supply it will list it like this .this is from a 400w power supply

+3.3V -> 20A Orange
+5.0V -> 40A Red
+12V -> 12A Yellow
+5VSB -> 2A Purple
-5V -> 0.5A White
-12V -> 0.8A Blue

see how this power supply has only 12a on the =12v rail ? that is borderline for todays systems .

here is another 400w power supply
Orange - +3.3V 28A
Red - +5V 35A
White - -5V 0.5A
Yellow - +12V 15A
Blue - -12V 0.8A
Purple - +5V Standby 2.0A
as you can see they are both 400w but have different specs .


i just rma'd a antec tru550 power supply . i was having the same problem random reboots , lost drivers , total system crashes . i tried everything because i didn't want to believe that the 110$ i spent 6 month earlier for the power supply was the problem . well after trying everything i could think of i switched out the power supply with one i had here i was going to put into another pc . and the problem stoped .... you don't give the full specs on your pc and you don't give the specs on the power supply but from what you are saying i would still blame the power supply . now you don't need to go get a bigger supply . 400w is a good type to get . you just have to make sure the "rails" are high anuff to support all the things in your pc . this might be a good read for ya http://www4.tomshardware.com/howto/20021021/index.html

IMO from what i read I don't see why anyone thinks its a psu problem...maybe an overheating psu...but not a bad one. Your cpu temps are a little on the high side but no higher than mine. As for compariing your problems to someone else thats allright for some ideas to look at and possible suggestions but ruling something out because it did or didn't fix his problem just doesn't work. Two computers with identical everything can still have seperate reactions to things.

I'd say its either A} your psu is overheating or you got a bad one from the rma B} your video card is overheating. C} your cpu fan might be part of the problem as well not sending a constant signal to the mobo and causing it to shutoff

Is that p/s the same exact make/model as the one before?? you can never rule out what omar said...

edit:damn fingers adding in those typos all the time

[vanik]

Just bought a new 400W power supply at the local comp store and still got the same problem

So I guess it's either a motherboard, cpu, or ram problem.. thats the only things that are left...