If you have an Nvidia GPU, under 'Manage 3d settings' in the Nvidia control panel, on the General page you see first, make sure DSR Factors are all off so it's not rendering at a higher resolution than necessary.The advanced settings (global) are accessed by clicking the link on the option pane shown above, or via Windows Settings > System > Display > Advanced scaling settings: In the April 2018 Windows 10 update this has changed a fair bit, you can leave everything unchecked if you make use of the new global override in the advanced scaling settings (shown further below): Right click the file and select Properties, then move to the Compatability tab and tick the Override/Disable High DPI option (yours may appear differently as this image is from the Win10 Creators Update released April 5th 2017). You might not see the '.exe' part depending on Operating System settings. Locate 'quakelive_steam.exe' via properties on Quake Live in your Steam Library -> Local Files -> Browser Local Files.Alt-enter switches between windowed mode and fullscreen, try that twice.If this is a problem in windowed mode try just alt-tab out of the client, and then resizing the window a tiny bit by dragging the edges or corners, that will make it pop out to it's minimum functional size and it should work from then, if not then try the other options here.
