What to do when the PC turns on but the screen remains black

0504 primary

When Harrison Bywater turns on his PC, the power lights and the fan turn on, but no image appears on the screen.

I'll start with the bad news: There's a very good chance that you'll have to take the PC into the shop. The good news: With a few simple tests, you might be able to avoid that expensive trip. Or, at the very least, you'll be able to come into the shop with enough knowledge to avoid being played a fool.

[Have a tech question? Ask PCWorld Contributing Editor Lincoln Spector. Send your query to answer@pcworld.com.]

I'm assuming here that absolutely nothing comes up on the screen. You don't see the Windows logo. You don't see the manufacturer's logo. You don't see a blinking cursor.

Whatever it is, it's a hardware problem. Windows is not to blame. Nor is your hard drive.

But what kind of screen are we talking about? I'll give you instructions for both an external screen and the one built into your laptop or all-in-one.

External monitor

As is so often the case, diagnosing and repairing hardware is much easier when all of the parts aren't enclosed in the same, tiny box.

First of all, check what happens to your monitor's LED light when you turn on your PC. Does it turn on or change color the way it did before the problem started?

If no light comes on at all, make sure the power switch is on and the monitor is plugged into an electric outlet. If it is, try another outlet.

Once you're sure it's getting power, check the cable connecting the monitor to the computer. Make sure you have solid connections on both ends.

If that doesn't solve the problem, try another cable.

Still no fix? Then it's time to swap monitors. This is easy if you have another monitor handy. Otherwise, bring your monitor to a friend's home and try it with their computer.

If the monitor fails on the other computer, you've got a defective monitor. Time to replace it.

Otherwise, try another graphics card.

A built-in screen

You have far fewer options with a laptop or all-in-one. For instance, if the problem were a loose cable connection, you'd have to open the PC, find the right cable within a very tight space, and figure out where it goes.

I generally don't recommend that readers try their own internal laptop hardware repairs. If you don't know what you're doing, you can easily brick the machine.

So what should you do? First, turn up the brightness. Study the keyboard for an icon that suggests turning up the light (for instance, the sun and an up arrow). Hold down the Fn key while you hold down whatever key has that icon.

You should also try using an external monitors. If this works, you at least know the problem is with the built-in screen.

At this point, I think you're going to have to take the laptop to a professional. But if you decide to ignore my advice and try to repair the screen yourself, read Eric Geier's instructions first.

To comment on this article and other PCWorld content, visit our Facebook page or our Twitter feed.
Shop Tech Products at Amazon
Notice to our Readers
We're now using social media to take your comments and feedback. Learn more about this here.