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Practical Computer Advice
from Martin Kadansky
Volume 14 Issue 8
August 2020
Black Screen: What to Try When Your Computer Won't Power On

The problem

Your Windows or Macintosh computer screen is blank, solid black. It was working earlier, but now you can't get it to turn on. What should you do?

First, try this simple technique that might revive your computer with a minimum of effort

One common reason that a computer won't power on is paradoxical: It might not really be off.

Sometimes a computer can get into an odd, "stuck" state, where it's not fully "off," but it's not "on" in any functional sense, either.

Try this:
  • For a laptop computer, open the lid and keep your eye on the internal (built-in) monitor; if you have an external monitor, ignore it for the moment.
  • Press and hold the power button for a count of 10-15 seconds. If the computer wasn't really off, this will probably fully turn it off.
  • Release the power button.
  • Wait a few seconds.
  • Then press and release the power button as you normally would to turn the computer on, i.e., don't hold the button down.
If your computer starts up, you've done it!

If not, keep reading for the rest of my advice.

Then, try this similar technique

Another potential problem is that some of the circuits and capacitors inside the computer may have built up excess electrical charges, so try this:

Try this:
  • For a laptop computer, open the lid and keep your eye on the internal (built-in) monitor.
  • Unplug one end of the computer's power cable from its back, its side, or from the other end where it goes into a power outlet, whichever is more convenient for you to reach.
  • For a laptop, take out the main battery.
  • Press and hold the power button for a count of 20 seconds. On many computers this drains away any excess stored electrical charge.
  • Release the power button.
  • Plug the power cord back in
  • For a laptop, put the battery back in.
  • Then press and release the power button as you normally would to turn the computer on, i.e., don't hold the button down.
If you're using an external monitor with your computer, check that next

If your computer has an external monitor:
  • Is the monitor's power switched on? Most monitors have a light that indicates when they are receiving power, typically red, green, amber, or white.
  • If you end up turning the monitor off and on again, and then you briefly see a message like "No signal" on the screen, that means that it is receiving power, but it's not receiving any video signal from your computer. That means that there might be a problem with the video port on the monitor, the video cable, the video port on the computer, the computer itself, or any combination of those elements.
  • Is the monitor's video cable plugged in to both the monitor and the computer? If not, that may be the problem. If so, try unplugging and re-plugging both ends of that cable. Did either end feel loose?
Next, check the power source

Find the power cord on the back or side of your computer and follow it to find its other end:
  • Is it plugged into an outlet that is actually supplying power? Test that outlet, for example with a working lamp that's already switched on (so it will light up when it gets power), or with a cell phone charger that's already plugged into a cell phone (so the phone's screen will tell you that it's charging when it receives power).
  • If you're using a surge protector and the power outlet in question is not providing any power, is the surge protector's main switch turned off? Could its fuse have blown?
  • Is there a wall switch in the room that controls that wall outlet? If so, is that switch turned off?
  • Could that wall outlet's fuse have blown, or could its circuit breaker have tripped?
Next, check the computer power cord

If the outlet is providing power, try this:
  • Unplug both ends of the power cord, both the end where it goes into the computer and the other end where it goes into the power outlet.
  • For a laptop, the power cord probably also has a transformer (a "brick" or "black box") along its length. Disconnect the cord at the transformer as well, separating the cord into two segments.
  • Did any of those connections feel loose as you pulled them apart? If so, that might have contributed to the problem.
  • If the cord has a transformer, reconnect the two segments.
  • Plug both ends of the cord back in, into the computer and the outlet.
  • Try to turn your computer on again.
If your computer has an external monitor, check its power cord, too

Try all of the above steps for the monitor's own separate power cord as well.

Other things to try

If you're still not sure where the problem is, here are some additional variations you could try in conjunction with my advice above, especially if you have access to spare equipment or a second computer:

If your computer has an external monitor:
  • Try your computer with another working monitor; that will help you learn more about whether your computer or monitor might be the problem.
  • Try your monitor with another working computer; that will help you know whether your monitor works or not.
  • Try another video cable; if that works, then there might be something wrong with your original video cable.
And if you have a laptop computer:
  • Take out the main battery, wait a minute or so, put it back in, and then try to turn it on.
  • Take out the main battery, and then try to turn it on. If that works, there may be something wrong with that battery.
Consider also labeling your cables

As you work on this problem, you're likely to figure out what many of your cables are and where they go. You could label them, especially:
  • Your various power cables; a good place to put a label is near each one's end where it goes into your surge protector or wall outlet.
  • The various cables that plug into the back or sides of your computer.
While this won't help make your computer start up, you may find it helpful in the long term.

Where to go from here
  • google: computer won't power on
  • google: computer monitor is black
  • google: computer black screen fix OR troubleshoot
How to contact me:
email: martin@kadansky.com
phone: (617) 484-6657
web: http://www.kadansky.com

On a regular basis I write about real issues faced by typical computer users. To subscribe to this newsletter, please send an email to martin@kadansky.com and I'll add you to the list, or visit http://www.kadansky.com/newsletter

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I love helping people learn how to use their computers better! Like a "computer driving instructor," I work 1-on-1 with small business owners and individuals to help them find a more productive and successful relationship with their computers and other high-tech gadgets.

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