Smart & Connected Life Working From Home How to Test a Computer Monitor That Isn't Working Nothing on the screen? Here's how to properly test your computer's monitor By Tim Fisher General Manager, VP, Lifewire.com Tim Fisher has 30+ years' professional technology support experience. He writes troubleshooting content and is the General Manager of Lifewire. our editorial process Facebook Twitter LinkedIn Tim Fisher Updated February 06, 2020 Working From Home The Ultimate Guide to Shopping Online The Ultimate Guide to Online Learning at Home The Ultimate Guide to Skype Tweet Share Email Is nothing showing up on your monitor? Fortunately, testing a monitor is one of the easier computer troubleshooting steps. By fully testing your monitor using a logical troubleshooting process, you can be confident that your monitor is or is not working properly and then take whatever action necessary to get back up and running. Testing a monitor could take from a few minutes to much longer depending on the cause of the problem How to Test a Computer Monitor That Isn't Working Follow these easy troubleshooting steps to test your monitor: Check to make sure your monitor is on! Some monitors have more than one power button or switch—confirm that they're all switched on. Check for disconnected monitor power cable connections. Your monitor might be working fine and your only problem may be a loose or unplugged monitor power cable. Also be sure to check for any cable adapters that aren't fully secured, such as a small connector that joins an HDMI or DVI cable to a VGA plug, or vice versa. A disconnected monitor power cable could be the cause of your problem if your monitor's power light is completely off. Check for disconnected monitor data cable connections. Again, your monitor might be turning on without a problem but no information can get to it because the cable that connects your monitor to your computer is disconnected or loose. A disconnected monitor data cable could be the cause of your problem if your monitor's power light is on but is amber or yellow instead of green. Turn the monitor's brightness and contrast settings completely up. Your monitor might be showing information but you just can't see it because these display settings are too dark. Most modern monitors have a single on-screen interface for all settings, including brightness and contrast. If it turns out that your monitor isn't working at all then you'll likely not have access to this interface. An older monitor might have manual knobs for adjusting these settings. Make sure all monitors are set up properly (if this is a dual-monitor setup). This step might seem too general, but if you're using two or more monitors, it's possible that the extended displays work just fine but the operating system isn't using them properly. This could be due to a number of things like a missing/corrupt video card driver or an incorrect setup procedure. For example, maybe a projector is connected to the laptop but not set up as an additional screen (so it remains black), or maybe the projector is configured as the primary display, and so the on-board screen is black. How to Add a Second Monitor in Windows Test that your computer is working correctly by connecting to your PC a different monitor that you're certain is working properly. Your monitor might be working fine but your computer might not be sending information to it. If the new monitor you connected doesn't show anything either, proceed to Step 7. If the new monitor you connected does show information from your computer, proceed to Step 8. When testing with the new monitor, make sure you use the data cable that came with it and not the one from your original monitor. Determine why your computer isn't sending information to your monitor. Since neither monitor works, you now know that the computer isn't sending information to the monitor. In other words, you've proven that your computer, not the monitor, is the reason that nothing shows up on your monitor. Chances are your original monitor is working fine but something else is to blame, like a disconnected or faulty video card, for example. Test your original monitor with a monitor data cable that you know is working. It's possible that the monitor itself is working properly but it can't receive information from the computer because the cable that connects the monitor to the PC is no longer working. If possible, test using the data cable from the monitor that you successfully tested earlier. If not, purchase a replacement monitor data cable to test with. The data cable on some older monitors are permanently connected to the monitor and aren't replaceable. In these cases, you'll have to skip this step and proceed to Step 9. If Nothing Else Works, Replace the Monitor A computer monitor isn't a user serviceable device. In other words: don't open the monitor and attempt to repair it yourself. If you'd rather have your dead monitor serviced instead of replaced, then please let a professional do it. The 8 Best Computer Monitors of 2020 If even that didn't work, you might not have had a monitor problem at all but instead there might be an issue with the rest of the computer system. As mentioned above, it's probably time to figure out why nothing is being sent to the monitor.