My computer/monitor won’t turn on at all – what do I check first?
First, don’t panic – nine times out of ten this is a cable or power issue, not a dead computer. Start by checking that the monitor and computer are both getting power and that the cable between them is seated snugly at both ends.
Quick things to check first
- Check that the monitor’s power cable is pushed in firmly at the wall and at the back of the monitor, and try a different outlet if you can – sometimes a breaker tripped and only half your outlets are live.
- Look for any little power LED on the monitor or the PC case; if there’s no light at all, the problem is power, not the display cable.
- Unplug the monitor from the wall, wait about two minutes, then plug it back in – this clears up glitches from power surges, like after an outage.
- Follow the video cable (HDMI, DisplayPort, USB-C) from the monitor to the computer and push both ends in firmly; if it’s loose, you’ll get a black screen even though everything has power.
- If you have a spare cable, swap it in – a bad cable is cheap to fix and a common culprit.
- Try plugging the monitor into another computer or a laptop if you have one; if it works there, your monitor is fine and the issue is inside your computer.
If that didn’t fix it
- Listen to the computer when you turn it on – if you hear fans spinning and the hard drive chattering but the screen stays black, the computer is running but not sending a video signal, which points to the graphics card or the cable.
- Run the monitor’s built-in self-test if it has one (check your manual or the on-screen menu); if the self-test pattern shows up, the monitor is good and the problem is the computer or cable.
- Try plugging the monitor into a different port on the back of the computer if you have more than one – some PCs have ports on the motherboard and on a separate graphics card, and only one set is active.
- If you can get display with the other port or another monitor, boot into Windows and check for graphics driver and BIOS updates through Windows Update or your manufacturer’s website; outdated or corrupted drivers can cause black screens.
- If the monitor has power but shows nothing on any computer, and you’re comfortable with a soldering iron, the issue may be blown electrolytic capacitors on the monitor’s internal board – but this is a repair for someone with electronics experience.
When to call a pro
Call a pro if the computer shows no signs of life at all – no fan noise, no lights, no clicks – after you’ve tried a different outlet and power cable; if you smell burnt plastic or hear a pop from the computer or monitor; if the monitor has power but won’t display on any computer and you’re not skilled at board-level soldering; or if you’ve reseated cables, tried another monitor, and updated drivers but still get a black screen with the computer clearly running.
Pro tip
Plug your computer and monitor into a surge protector or battery backup so a sudden outage doesn’t fry components. When you reconnect cables, give them a gentle but firm push – a cable that’s just barely in can cause hours of head-scratching. And before you panic, try the simplest thing first: power everything down, unplug for a couple minutes, and plug back in.