Computer turns on but no display after power outage

I was on my PC when the power cut out. It is hooked up to a surge protector/power strip. When I tried turning it on, all of the fans and LEDs turn on, but the computer does not boot. There also is a beep which I found out from the mother board manual means VGA is detected, quick boot is disabled and keyboard is not detected. The keyboard is plugged in and the numlock light turns on. The monitor does not display anything other than no signal. The fans are plugged into the motherboard. Can someone help me figure out the source of the problem?

Edit: Wow didn't realize I could edit this 6 years later. My solution was to take out the CMOS battery on my MOBO and wait 15 min, then put it back in and everything worked perfectly.

It’s happened to all of us: you sit down with the intention of doing some work on your computer, only to see nothing but a black screen when you try turning it on.

In 95% of cases where a computer or laptop simply won’t turn on, it is due to power (hydro) issue, like power surges or brief brownouts.

Will A Power Surge Damage My Computer?

Power outages themselves will not usually cause any damage to your computer hardware. However, in some cases power outages are also accompanied by power surges—it’s those surges that you need to worry about damaging your computer (and other electronics).

A power surge can have a number of consequences for your computer, including:

• Damaged motherboard
• Damaged hard drive
• Slow performance
• Inability to hold a battery charge

To avoid these problems, it’s a good idea to use a surge protector with your computer, whether it’s a desktop or a laptop. This will help make sure that if there is ever a power surge, your computer is protected and doesn’t take the brunt of any electrical damage.

Keep in mind, even if you have a ‘proper’ surge protector, if the power is off for even a few seconds, it can have an effect on your computer. Even if your computer isn’t damaged, it may give you issues booting up after an outage.

The good news is there are some simple tests you can try to get your computer up and running again.

What To Do If Your Computer Won’t Boot After A Power Outage

First, try turning on your computer: if the ‘green’ light comes on and you can hear the fan, but nothing happens—it’s a sign your computer has been affected by a power surge or outage.

1. Unplug the big black power cable from the back of the computer. If it’s a laptop, remove the battery as well
2. Hold the ‘on’/power button your computer
3. Wait 5 seconds
4. Press the power button to ‘turn off’ your computer
5. Plug in the big black power cable from the back of the computer again
6. Turn on your computer

If this fixes the issue, you should be fine. You have just purged the “dirty power” from your computer, and your computer power supply is fine. The same could be accomplished by letting your computer sit turned off for several hours or days, but who wants to wait that long?

If that solution doesn’t work, or the lights and fans don’t turn on when you try turning on your computer, there are a couple other fixes you can try to diagnose the problem:

Check Your Power Source

If your computer won’t turn on at all, check the outlet, powerbar, or power source it is plugged into. If it is plugged into a surge protector, it’s possible that it was tripped during the power surge.

To test, remove any power strips, battery backups, or other power sources, and plug your computer directly into a wall outlet. If your computer starts after doing this, it means a surge may have fried whatever power source you were using and will need to be reset or replaced.

Check Your AC Adapter

If your laptop battery doesn’t seem to hold a charge, your AC adapter may have been damaged by the surge. Dirty power from power surges or brownouts can also affect your AC adapter, causing it to stop properly charging your battery.

Check Your Battery

If you’re working with a laptop, take out the battery and try booting it using AC power. If your computer starts up without any problems, it is likely an issue with your battery and will need to be replaced.

Check Your Computer Fans

If your computer’s fan doesn’t start when your power supply is turned on, it could mean that your power supply needs to be replaced. Issues with the computer fan not running could mean there is a problem with the motherboard or CPU, which may need replacing.

Check your CPU (Central Processing Unit)

When the computer power is on, check for a green light on the motherboard by looking through the vents on the side of your computer.

If you see a flashing green light, the Power Supply Unit (PSU) likely needs to be reset. If there is no green light at all, the Switched-Mode Power Supply (SMPS) unit may have been damaged from the power surge and may need to be replaced.

Call Your Local Nerd

If you’re not able to figure out why your computer won’t turn on, or aren’t sure how to fix the issue, a professional can help. Our team of Nerds will diagnose the problem and have it fixed to get your computer back up and running.

• If you are sure that the monitors are still good I would start by simply re-seating the memory and graphics card then move to the power-supply if that does not work. Also if try the on-board graphics, if available, with the card out and see if you get any output there.

  Power loss is never fun for IT.
  

• Were you not running a surge suppressor on every machine?

• cakuhn80 wrote:

  I have to machines that have no video input after a power outage.  After powering them back up there are no beeps, and i can hear fans running.  Monitors are working fine.  Im thinking power supply, or video card first.  

  To machines with no video input?
  
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• We had a batch of PCs once and about 1/3rd of them had that issues after every power outage. To correct it we had to unplug them from power and discharge all of the capacitors and after that they would power on normally.

  Can you ping the two PCs in question? If you can have you tried accessing them remotely (RDP or VNC)?

• Try reseting the power supply. Unplug the PS from AC power, hold power button down for 20-30 seconds. Plug back in and try to boot up.

  EDIT - Just seen CTMorseJr   post. He beat me to it.

• Thanks for the input. No pun intended..

• Assuming you mean video output? If your video input is missing, well that's black magic you can't fix.

  Everyone has mentioned possible solutions. First things first, is the computer up and running? try to ping it. that tells you the network card is working.

  If the ping is good, then try another monitor. If that does not work, try re-seating the video card (if it is not on-board), or if it is on-board and you have an extra video card laying around, try that. 

  If all this does not work you can check for a faulty power supply. After this I'd say something went in the MoBo.

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• Unfortunately these are a vendors PC, and we only support I site fixable issues for them. Just found this out. Thanks for the input. I will try and reply.

• Try reset the BIOS first and remove the RAM...
  

• cakuhn80 wrote:

  .... after a power outage.  After powering them back up there are no beeps, and i can hear fans running. ...  Im thinking power supply, ....
  

  
  

  CTMorseJr wrote:

  .... had that issues after every power outage. To correct it we had to unplug them from power and discharge all of the capacitors and after that they would power on normally.

  What you have both described is typical behaviour for faulty capacitors in power supply. Change power supplies. You need to wait first 5-10 minutes for computer to turn on. And it gets longer and longer. See here details.

  http://community.spiceworks.com/topic/748764-xerox-colorcube-8570-power-supplies

  Simple and fast check. Open the computer and power supply and visually identify faulty capacitors including on motherboard.

• Power off the PC.

  Unplug the power cord from the PC.

  Hold the power button for 10 seconds to discharge capacitors as mentioned in other posts.

  Plug back in the PC and attempt to power on.

• Thanks for the replies!  One was discharged and fixed the issue.  The other I reseated the video card and it's up and running.  Much appreciated. 

• Everything is good and got both machines to power on again.  The user was using a backup machine with 3 monitors.  When I switched over to the original machine, I can't get video again out of one of the ports, which happens to be the desktop.  So, the user said just switch me back to the other machine for now.  When I switched, now there is no signal from this port on the machine that was just working when I walked in his office.  The port thats giving me trouble happens to be an old dual DVI D port.  This is the port that the desktop is displayed on for the user in the first place.