The good news: By going through a few simple tests, you may be able to avoid this after all and solve the problem on your own. And even if it doesn’t work, at least you can know what the problem is so that the service is faster and costs less, and you don’t get scammed.
We assume here that the screen is completely black and does not light up at all. No Windows logo, no manufacturer logo – nothing.
Whatever the cause, it’s all about the hardware in some way. Windows or OS X is not the problem, and neither is the hard drive.
But what kind of screen are we talking about?
With computers where the various components are independent and not crammed into a small box, it is usually easier to diagnose various errors, and this is also the case when the screen remains black.
The first thing you should check is what happens to the screen’s LED when you turn on the computer. Does it change color like it used to before you had the problem?
If it does not light up at all, there may be a problem with the power supply. Check that it is plugged in properly and that it is turned on. If that doesn’t work, try another jack to make sure it’s not the wall outlet that’s broken.
Once you’re sure it has power, check that the cable between the monitor and the computer is plugged in properly. If that doesn’t work, try a different cable (and if both the screen and the computer have several different connector types, you can try changing from, for example, hdmi to dvi).
If it still doesn’t work, it’s time to try another screen. If you have another screen handy, you can test with it. Alternatively, you can test your own screen in another computer that you have at home or at a friend’s. If the screen doesn’t work with other computers either, it’s broken somehow. If you still have a warranty, it will be used. If not, and if the screen wasn’t a really expensive story, it will probably be time to buy a new screen.
If the screen works in other computers, it may instead be the graphics card that is broken. If you can replace the graphics card, you can try another one. Otherwise, you may return the computer for service.
You have significantly fewer choices if you have a laptop or an all-in-one computer like Apple’s Imac or HP Envy. For example, if the problem is a loose connector, you’ll need to open the computer and find the right side of the right cable just to test if that’s the case.
In general, we cannot recommend trying to fix problems in these machines on your own. If you don’t know exactly what you’re doing, it’s easy to accidentally screw up your computer even more.
So what can you do then? Start by turning up the brightness. There seems to be a button for that among the function keys. Test both with and without the Fn button.
You can then try plugging in an external screen and see if it works as usual. If it does, you are at least certain that the fault is in the built-in screen, and have more on your feet when you take the computer in for service. If it still doesn’t work, it’s probably something else, like a broken graphics card.