What causes a flashing computer screen
A flashing screen usually means one of three things: a loose or faulty cable connecting your monitor to your computer, a graphics driver that needs updating, or a refresh rate set too low for your monitor. Less often, it's a failing monitor itself or interference from nearby electronics. The good news is that most of these are fixable without calling a technician.
The first step is to figure out whether the flashing happens right when you turn on your computer, only in certain programs, or all the time. That tells you whether the problem is hardware or software. A screen that flashes constantly from startup is usually a cable or monitor issue. A screen that flashes only in one program or after a recent update usually points to your graphics driver.
Key Takeaways
- Check the cable connecting your monitor to your computer tower or laptop dock first — a loose or bent cable causes flashing in seconds.
- Update your graphics driver through Device Manager (Windows) or System Preferences (Mac), since outdated drivers are the most common software cause.
- If flashing started after a Windows update, roll back your graphics driver to the previous version rather than updating further.
- Lower your monitor's refresh rate in Display Settings if it is set above what your monitor supports — 60 Hz works on almost all monitors.
- If the screen flashes only in one program, that program may have a graphics setting you need to adjust, or the program itself may need updating.
Check your monitor cable first
Before you change any settings, look at the cable running from your monitor to your computer. On a desktop, this is usually a cable with a blue connector (called a VGA cable) or a white or black connector (HDMI or DisplayPort). On a laptop, it's the cable going to your docking station or external monitor.
Unplug the cable completely from both ends, wait five seconds, and plug it back in firmly. Make sure it clicks or seats all the way — a cable that is halfway in will cause flashing. If the cable looks bent, kinked, or frayed, replace it. If you have a spare cable, swap it in to test whether the original cable is the problem.
Also check whether anything is sitting on the cable or pulling it tight. Move any objects away and give the cable slack. If the flashing stops after you reseat the cable, you have found your answer.
Update your graphics driver
Your graphics driver is the software that tells your computer how to talk to your monitor. When it is outdated or corrupted, your screen often flashes. On Windows, you can update it through Device Manager without downloading anything from the internet.
Right-click the Start button and select Device Manager. Look for Display adapters and click the arrow next to it to expand the list. Right-click the graphics card listed there (it usually says Intel, NVIDIA, or AMD) and select Update driver. Choose Search automatically for updated driver software. Windows will check for a newer version and install it if one exists. Restart your computer when prompted.
On a Mac, go to System Preferences, then Software Update, and install any updates available. Mac updates often include graphics driver fixes. If you are using an external monitor on a Mac, also check the monitor manufacturer's website for a driver specific to your model.
If flashing started right after a Windows update, your new driver may be the problem. In that case, right-click the graphics card in Device Manager again, select Properties, go to the Driver tab, and click Roll Back Driver. This reverts to the previous version. Restart and see whether the flashing stops.
Adjust your refresh rate
Your monitor's refresh rate is how many times per second it redraws the image on screen. If this is set higher than your monitor can handle, the screen flashes. Most monitors work at 60 Hz, but some older ones work only at 50 Hz or 30 Hz.
On Windows, right-click your desktop and select Display settings. Scroll down and click Advanced display settings. Look for Refresh rate and click the dropdown. Try setting it to 60 Hz and click explore. If the flashing stops, you have found the problem. If 60 Hz is not available, try the next lower option.
On a Mac, go to System Preferences, then Displays. Click the Scaled or Resolution option and look for a refresh rate dropdown at the bottom. Select 60 Hz and see whether the flashing stops.
Look for interference and overheating
Wireless devices, microwaves, and cordless phones can sometimes interfere with monitors, especially older ones. If your screen flashes only in one location, try moving your monitor away from other electronics. Unplug any USB devices you do not need and see whether the flashing changes.
Overheating can also cause flashing. Make sure your computer has good airflow — do not cover the vents on your tower or laptop. If your computer feels hot to the touch, shut it down and let it cool for 15 minutes before turning it back on. If it overheats again quickly, dust may be blocking the fans. A can of compressed air can help, but if you are not comfortable opening your computer, a technician can clean it.
Test in Safe Mode to rule out software conflicts
If your screen flashes only sometimes or only in Windows (not in the BIOS or boot menu), a program running in the background may be causing it. Safe Mode loads Windows with only the essential drivers and programs, which helps you figure out whether a third-party program is the culprit.
On Windows 10 or 11, hold the Shift key and click the Power button, then select Restart. When the menu appears, select Troubleshoot, then Advanced options, then Startup Settings. Click Restart and then press 4 or F4 to enter Safe Mode. If the flashing stops, a program you installed is likely the cause. Restart normally and uninstall any recently added software.
On a Mac, restart and hold Command + S to enter Safe Mode. If flashing stops, restart normally and check for updates to any programs you recently installed.
When to replace your monitor
If you have checked the cable, updated your driver, adjusted the refresh rate, and the screen still flashes constantly, your monitor itself may be failing. Monitors typically last 5 to 10 years. If yours is older than that and flashing started suddenly, replacement is usually cheaper than repair.
Before you buy a new monitor, ask a technician to confirm the monitor is the problem, especially if your computer is still under warranty. Some repairs — like replacing a failing power supply inside the monitor — are possible but not common.
Frequently Asked Questions
Does a flashing screen mean my computer has a virus?
Not usually. Flashing is almost always a hardware cable issue, a driver problem, or a refresh rate mismatch. Viruses cause other symptoms like slowness, pop-ups, or unexpected programs opening. If you suspect a virus, run a full scan with Windows Defender or your antivirus software, but start with the cable and driver checks first.
Why does my screen flash only when I use one program?
That program may have its own graphics settings that conflict with your monitor or driver. Check the program's settings menu for display or graphics options and try lowering them. Also check whether the program needs an update — go to Help or Settings and look for a Check for Updates option. If the program is old and no longer updated, it may not work well with your current graphics driver.
Can I fix a flashing screen on a laptop without taking it apart?
Yes. Start with driver updates and refresh rate adjustments — those fix most laptop flashing without opening anything. If you use an external monitor with your laptop, check the cable and the docking station connection first. If the laptop's built-in screen flashes, it is usually a driver issue. Taking a laptop apart to replace the screen cable is possible but requires care and is best left to a technician.
What should I do if my screen flashes right after I spilled liquid on my keyboard?
Turn off your computer when ready and do not turn it back on. Liquid can damage internal components and cause electrical shorts. Let the computer dry completely — at least 24 hours in a warm, dry place — before powering it on again. If the flashing continues after drying, or if the computer does not turn on, contact a technician. Do not attempt to clean the inside yourself.