Computer screens can go blank and give the “no signal” message for various reasons. Here are a few of the more common ones:
- The computer has gone into standby mode
- The power supply is dead or malfunctioning
- There is a problem with the monitor itself
- The monitor is turned off
- The cable connecting the computer to the monitor is bad
- There is a problem with the computer’s graphics card
If your computer screen is completely dark or says “no signal,” there are a few things that you can do to troubleshoot the issue:
Move the mouse or press the spacebar on the keyboard
Most computers will go into “sleep” mode, also called standby mode, after a period of inactivity. This mode will usually turn off the screen, hard disk, and other devices to save power and wear and tear. If your computer is in standby mode, the screen may appear black or display a “no signal” message. You can usually wake it up by clicking or pressing the spacebar or moving the mouse to wake up a computer in standby mode. If moving the mouse or tapping the keyboard does not work, you can try pressing and releasing the power button to wake up the computer. If you have a laptop, closing and opening the lid can wake the device from standby mode.
Check the monitor’s input source setting
Most monitors have an input source selector that allows you to select between two or more input ports that are built into the monitor. Monitors will typically auto-select the input with an active signal, but sometimes that auto-select does not work for whatever reason. To use this test, you need to ensure that the monitor is not in auto-select mode. If it is, it will not allow you to select the input source. Check your monitor’s manual for instructions on how to access this function, then try manually toggling through the available inputs on the monitor.
Check the monitor resolution and the OS screen resolution
Monitor resolution and OS screen resolution settings are two crucial factors to keep in mind. “Resolution” refers to the number of pixels vertically and horizontally that your operating system uses when displaying text and images. A black screen can result if you attempt to set your screen resolution to values that your graphics card or monitor does not support. Fortunately, your computer will automatically revert to a supported resolution after fifteen seconds or so, allowing you to adjust the setting to something supported. Here’s how to set screen resolution in Windows and macOS.
Update Your Graphics Card Drivers
If you are experiencing a blank screen, there is a good chance that your graphics card drivers are outdated, especially if you’ve just installed a new monitor. Updating your drivers can fix many common problems and give your computer a performance boost. To check for graphics card driver updates on Windows, head to the Device Manager and select Update Driver Software. On macOS, go to Apple menu > System Preferences > Software Update.
Check the computer
Most computers have a power button that lights up when the computer is on – check that to verify that your machine is powered up. If not, make sure that the computer’s power cord is plugged in securely and that the outlet is working – try a different power cord or a different outlet if you have doubts about either. If you’re using a laptop, make sure that it’s fully charged and turned on. Next, try starting your computer by pressing and releasing the power button. If that does not work, or if the power indicator is lit, but you see nothing on your screen despite trying to wake up the computer (see above), try restarting your computer by pressing the power button for about 20 seconds. If it still doesn’t work, try disconnecting all of your cables from the back of your computer, turning it off for a few minutes, then reconnecting them one at a time.
Check the monitor’s power cord
Your monitor may look like it’s plugged in, but the power cord can potentially become loose both at the wall outlet and where it connects to your monitor. It’s always good to check the power cord for signs of damage and make sure it’s plugged in securely at both ends. If there are any signs of wear, such as kinks in the cord, frayed or broken insulation, or if you’re not sure whether the power cord is working, try a different power cord if you have one.
Check the video cable
If you’re using a computer with a separate (not built-in) monitor, make sure the video cable is firmly plugged into both devices. Many monitors have very stiff connections and can be difficult to get in place securely. Sometimes a loose or incorrect connection can cause problems with your computer. Also, check the cable for any signs of wear or damage, and if you have a spare cable, try that.
Make sure the outlet is working
Power outlets can develop problems, such as wear or dirt on conductive parts, loose wiring, and other issues that can cause a formerly working power outlet to no longer work reliably. If your computer monitor is not showing a picture, it might be time to check the outlet. The simplest way to test an outlet is to plug a different device into it that you know works, such as a desk lamp or a device that has a power indicator light. If the outlet is working, your problem lies elsewhere. If you have a surge protector or power strip between the wall outlet and your monitor, that is also a potential failure point, so test that with a known working device or bypass it with the monitor’s power connection to see if that helps.
Try a different monitor
If you have a spare monitor, try plugging that into a power outlet and connecting it to the computer to see you get a picture. If you see an image, it’s likely a problem with your original monitor. Assuming that you had already checked the old monitor’s power and video cable connections before trying this test, the monitor itself may have failing internal components requiring repair or replacement.
Internal hardware issues
If you have tried all of the above steps and you still cannot get an image on your monitor, there may be a problem with your computer’s graphics card. A graphics card is the part of the computer that displays images on the screen. Some computers have built-in display hardware as part of the mainboard, while others support or use separate expansion cards to handle graphic display. Computers run hardware checks before the operating system loads during startup. If you have a graphics card problem, your computer should beep at you and stop responding during the startup process. If this happens, you’ll want to take your computer to a service center so they can confirm the issue and repair the computer. While you can purchase a replacement graphics card and install it yourself, you will need to be comfortable with opening up your computer’s case and working with its innards if you go that route.
In conclusion, if your computer screen is blank or says “no signal,” there are a few things you can do to try and fix the problem. Some of these solutions are simple, like restarting your computer, and others may require more technical know-how. If you’re having trouble getting your computer screen to work, don’t panic! There are plenty of resources to help you out, like online support forums and tech-savvy friends. If all else fails, take your computer to a technician for further assistance.