how to find out which renpy version used for games?
For a game you've actually installed, look inside the game folder for a script_version.txt file.
Open it in a text editor like notepad & it will have something like
(7, 4, 4) = version 7.4.4
Though if you can't update the graphics driver and switching renderer doesn't work, then your only option might be to downgrade the version of Ren'Py the game is using. Make sure you have a backup of the game before trying this:
1. Find a Ren'Py game that still works on your machine (old-game).
2. Go to the game which doesn't work (new-game), and delete the "lib" and "renpy" folders.
3. Copy the "renpy" and "lib" folders from the old-game into the new-game.
Downgrading might not work if the game uses any new features, and it may break old saves.