I get questions that boil down to this symptom quite often.
Unfortunately, it’s very hard for me to offer concrete help.
The problem is that there are so many possibilities that could lead to this symptom. There’s simply no single “part of my computer” to point at.
There are many things to look at, and look for, so I’ll review the most common causes and remedies.
Become a Patron of Ask Leo! and go ad-free!
Most common: overheating
A suddenly black screen accompanied by what appears to be a completely unresponsive computer is, most often, a symptom that you computer has crashed.
And the most common cause of crashes is overheating.
Your computer needs good ventilation to avoid overheating. Make certain that the ventilation holes aren’t blocked by dust or other debris.
Occasionally, a poorly-designed computer can overheat even if there are no obstructions. Most often this is because the CPU is being used too heavily for too long. This can be due to malware, which I’ll discuss in a moment, or it can be due to running a CPU-intensive program or game continuously for a long time. If the latter is the case, you may need to take steps to provide extra ventilation, or cool the air flowing around or through your computer.
Hardware does fail. One of the early signs of impending failure is a periodic crash such as you describe.
Given that it’s consistently happening 5 to 15 minutes after boot up, after looking at possible overheating issues, I’d probably begin to suspect the power supply next.
Just about any hardware component on your computer can cause a crash if it’s starting to fail. Most often it’ll take a technician looking at the machine in person to diagnose imminent hardware failure.
In addition, drivers related to the hardware can also come in to play. If you’ve recently updated drivers for a component, it’s possible that the new drivers brought a problem with them in the form of a bug.
The next step would be to notice any correlation between the time the problem started and any software updates on your machine, particularly drivers related to the hardware.
Malware remains a possibility, though not to the same degree as it has been in the past.
To begin with, most malware isn’t really interested in intentionally crashing your computer. However, as you might imagine, malware doesn’t have quite the quality-assurance process that most commercial software has, so it’s possible that buggy malware could cause problems.
The reason that malware is less likely is that, unlike hardware drivers, it simply doesn’t operate at the same level needed to cause an instant and total crash. Malware-related crashes are usually limited to a single program, some specific functionality that stops working, or in the most common worst-case scenario, the “blue screen of death“.
But it remains something to stay on top of, via a complete and up-to-date anti-malware scan.
Perhaps not the computer, but the display
One more common “black screen” failure mode is that the computer’s display has stopped working, but the computer itself is still running properly.
One simple way to determine if this is what’s happening is to play some audio on your computer. Load up a longish mp3 play list or streaming audio station and let it play. If the monitor suddenly goes black, but the music continues to play, you know that the computer is still running, and that the problem is more likely either the video card, the video drivers, the monitor, or the cables connecting the monitor to the computer.
If that’s what appears to be happening, then:
- Check the connecting cable, making sure that the connections at both ends are snug.
- Borrow a replacement monitor to see if that resolves the problem (you would hook it up as an external monitor, if this is a laptop we’re talking about).
- You can also try updating the video drivers.
Unfortunately, diagnosing the video card itself can be difficult, and once again is something often best left to hardware technicians.
It could be expected and normal behavior
It’s probably obvious to you already, but I’ll say it anyway: it could just be a screen saver. If you wiggle the mouse or hit a key on the keyboard and your screen comes back, that’s it. You can adjust screen-saver behavior in the Display portion of Control Panel.
If you have a laptop, it’s possible that the computer has gone into Standby or Hibernate mode. If you simply push the power button and it comes back up to where you were after a few seconds, that’s probably it. Normally a computer should only go into Standby if you’re not actively using it, but if your battery is very low, it may force Standby in order to avoid losing your work in progress. Usually there’s a message that should tell you when this happens.
So as you can see, it’s not a simple process to diagnose. Some steps, like trying another monitor or cable, are pretty easy for you to take yourself. But if you’re not comfortable diagnosing system crashes or hardware problems like potential overheating, it might be time to take the computer to a local technician for a hands-on diagnosis.