rF2 starts normal and get into the main menu. I can hoover my mouse everywhere , all menu items lit up. As soon as i click on a menu item (car, tracks, options, start...it does not matter which i click, with all menu items the same happens but in this expample i use <start> to actually start my pre defines session). So i hoover my mouse over the large <start> button. It lits up and i click once. Normal behaviour would show the loading screen. From this morning, the screens flickers a few time and after two seconds or so, rF2 keep presenting the main menu. But now, my mouse pointer has a slight delay. Like of the sessions has started but its hidden. So i press <start> again. Now rF2 shows the loading screen and puts my car in the pits. But the performance is really bad. The FPS is 140 but game lags like hell. Only thing to do is closing down the game. I have done a file intergrity check twice but that did not help. Very frustrating as i wanted to do a race, which i can't. And please do not tell me to do a full reinstall as that will take half a day.
Check your video settings. Start Launcher / Settings (cog icon ) / Video Settings. Make sure GPU is set to your video card not to Auto.
And please don't ever do a full reinstall, 98% is just content files you already have. You achieve as much by removing a few select folders and running an integrity check.