Cannot run a game

When i try to run game from launcher, button gets pressed, then says game running, but nothing is showing and after some seconds button returns into “Play”. Started occuring long ago, after some update. Nothing helps (I’ve TRIED EVERYTHING, what could be already found, so plz, no more “update drivers, delete folder in appdata, change region, do something with security programms, use repair tools or close background applications” - nothing helps!!!).
EDIT: Just realised that the game is on Unity engine… which is kinda doesn’t run on fullscreen on my PC. New question - how i could turn game into windowed mode without launching it? If it possible to share saved settings for game - it would be really helpful to get settings with windowed mode on.
EDIT 2: Found a solution: I made all steps I do, when i need to run unity engine based game - opened my AMD settings, set game into powersaving mode (making it to run on integrated videocard) and launched it. While very laggy, game launched. Then i proceeded into setting and turned on windowed mode and closed game. In AMD settings returned high perfomance mode for a game and perfectly runnded game. In the windowed mode, like other Unite engine based games.
Thread may be closed, but the solution may help other peoples with old PC, who stumble onto same problem.