If your game screen is flickering, flashing, or showing 'tears' in the image, it usually means the game and your video card are having trouble staying in sync. The information provided below can help to stabilize your display.
Adjust High DPI & Full-Screen Optimizations
Windows often tries to 'enhance' older games, which can cause the image to flicker as it struggles to scale correctly.
Right-click your game icon and select Properties.
Go to the Compatibility tab.
Check the box for Disable full-screen optimizations.
Click Change high DPI settings, check the Override box at the bottom, and set the dropdown to Application.
Click OK, then Apply.
Disable 'Hardware Acceleration' (If available)
Some games have a specific setting called 'Hardware Acceleration' that assists in rendering graphics. If this is poorly optimized for your modern card, it causes flickering.
Open the game and go to the Options or Settings menu.
Look for Hardware Acceleration or 3D Acceleration.
If it is checked, uncheck it. If it is unchecked, try checking it.
Close and restart the game to see if the flickering stops.
Force a Refresh Rate Cap
Many older games were designed to run at 60Hz. If you have a high-end monitor running at 144Hz or higher, the game may flicker because it can’t keep up.
Right-click on your Desktop and select Display Settings.
Scroll down and click Advanced Display.
Look for Choose a refresh rate and set it to 60 Hz while you are playing the game.
Change the 'V-Sync' Setting
If you have an NVIDIA or AMD graphics card, your card might be forcing 'Vertical Sync' on the game.
Open your NVIDIA Control Panel or AMD Software.
Look for Manage 3D Settings.
Find Vertical Sync and set it to Off (or 'Let the application decide').