My computer won't power up

[Atropos13]

Originally posted by: mechBgon
Troubleshooting starter

1. Overview of the problem
   My computer will not turn on at all. It will not even POST or demonstrate any power is running through the system.
   
   
2. Full description of the problem and symptoms
   Ok, so I was playing a game (Neverwinter Nights 2 if anyone is interested) and without warning my computer instantly turned off. There was no BSOD or any warning signs. All my peripherals were still on (monitors, speakers, etc.) so it seemed it wasn't a breaker issue in my apartment. I tried restarting the computer but nothing happened. I checked all the power connections and they all look good and I tried a difference outlet, and still no change. When I flick the power switch on the PSU itself I occasionally see one of my case lights flash once and the PSU fan tries to start to move but then it stops immediately (maybe 1/40 of a rotation). To be clear, when I am hitting power switches, nothing happens, no POSTing or any activity with the computer.
   
   
3. Did it work normally at one time, or has the problem always existed?
   It has pretty much always worked right. My video card died about 3-4 months ago and my system wouldn't POST, but all the case fans came on at least. I had the card fixed and the system had worked fine after that.
   
   
   
4. Is the problem consistent and repeatable, or entirely random, or semi-random?
   It is completely consistent.
   
   
   
5. I already tried these steps:
   My first thoughts are either my PSU died or my mobo is fried. I tested the PSU using the "paperclip test" and it powered up just fine, so PSU isn't the problem. I don't have a way that I know of to test the mobo so I sent it to the manufacturer assuming it was defective. They sent it back to me saying they tested it and everything was fine with it. They suggested creating a "test bench" to test things, meaning to install my CPU, RAM, and video card in my mobo, hook up a monitor and all the power connections, connecting the power switch from my case, and see if it will at least POST. So I tried that but still get the same problem.
   
   As mentioned above, I have checked all the cable connections and tried different outlets.
   
   I am really at a loss of what else could be wrong. If it was a problem with the CPU, RAM or video card, wouldn't I at least get into POSTing? Or at the very least, I would think my case fans would turn on showing there was power running through the system.
   
   
   
   
6. My software:
   • Vista 32 with all the latest service pack and all the latest updates
   • Antivirus: AVG - Free Edition
   • Firewall: Windows software firewall
   
   
   
7. My hardware
   • System brand & model: I built it myself.
     
   • Gigabyte N650SLI-DS4L (nForce 650i/Socket 775)
   • Intel Core 2 Duo E6550 2.33 GHz
   • 4 GB G.Skill DDR2 800(PC2-6400)
   • Evga/nVidia 8800GT video card
   • Seagate Barracuda 7200 RPM 250 GB HDD
   • OCZ GameXStream (OCZ700GXSSLI) 700W ATX12V PSU
     
   
   
8. Other information that might be relevant
   Nothing else I can think of at the moment. Thanks for any help!
   

 

[jdjbuffalo]

It sounds like what happened was a power surge. This often at least takes out the power supply.

If it's not posting then there are very few possibilities.

Did you try plugging it directly into the wall? A bad power strip can cause this kind of issue.

Since the motherboard manufacturer stated that it worked fine for them, we're going to assume there is no issue with the device itself. However, one thing to make sure of is that if you are using metal stands, make sure they aren't contacting anywhere but where you have a hole in the motherboard and a screw to hold it in place.

The fact that the power supply doesn't stay on and the fans don't rotate is rather strange. This by itself would lead me to believe it was the power supply (75% chance). Now, you said that you were able to jump it and it worked. I would not expect this but there is still a possibility that it could be a bad power supply (under 50% chance).

When you did a bench test, did you try only on RAM stick in your motherboard? Did you try each stick in more than one slot?

If you have a friend that has a video card (any PCI-Express card will do) and/or a power supply then try and get that from them for a day so you can do some testing. If you can't do that then I would recommend going down to your local computer store that has a return policy and getting a power supply. This way you can test to see if this is the problem. If it doesn't fix the problem then you can return the power supply.

If you've done all of the above and your system still won't power on then I would say it is very likely a bad CPU (90+%). If you got the boxed Intel processor then it should have 3 year warranty. You should be able to get Intel to replace it, provided it doesn't have any physical damage.

 

[jackschmittusa]

I would think it quite rare for a cpu to fail in a working rig if the mb is still OK. It would have likely had to have gotten really hot for an extended period for that to happen. Is there a thermal alarm set in your bios?

While the "paperclip test" is not an absolute indication that everything is OK with the psu, it is enough to make me look at other things first.

The first thing I would try is a different video card. I keep an ancient pci card around for testing. Not only does that leave the original card out of the equation, but its slot as well, and it requires no extra power connection.

Keep doing any further testing on the bench as it eliminates a slew of possible problems that could occur when it is in the case.

 

[jdjbuffalo]

I agree bad CPUs are rare but they do happen.

 

[mpilchfamily]

In most cases if a PC soudenly turns off and there wasn't a power outage or surge from a high power device on the same curicut powering up then its a dead PSU. Its not uncommon for the Gamerxtremes from OCZ to go out like that. SO go out and get another PSU and you should be good to go. Its very unlikly that the PSU damaged anything when it died. OCZ makes decent PSUs and they are no known for damaging systems when they die.

 

[Atropos13]

Thanks for the replies everyone. I had forgotten to mention that soon after this all happened I went to Best Buy and got another PSU and nothing changed. I am tempted to try that again though, in case I got a bad one from the store (unlikely I know, but that kind of thing has happened to me before). While I am there I will get a cheap video card so I can test that as well.

As far as the test bench goes, I was hoping I get clarify if I am doing it right. I install the CPU/heatsink/fan, RAM, video card and then I attach the the PSU to the main mobo plug, the video card, and the CPU plug. And then hook up the monitor. From here I am unsure if I need to attach the power switch lines from my case to the mobo or make any other connections or just turn on the PSU. At this point from what I understand I should see it POST if everything is ok. I have never done the test bench until my computer died this time, so it is new to me. That would really suck to be doing the test bench wrong all along the way. Thanks for the help!

 

[jackschmittusa]

When bench testing, you can use a pocket screwdriver to short the 2 pins on the mb for the power switch. Momentary contact is all that is needed.