Hello asgerlycke,
Based on the description you have provided, it seems that the problem you have is a compatibility issue. Even Though Win 8 is similar than Win 8.1 these two operating systems have different platform or kernel meaning that the software that works in win 8 not necessarily will work on win 8.1.
Since you have tested the latest driver in win 8.1 from our side, I recommend you contacting the game developer and confirm with them the OS compatibility or contact the computer manufacturer for the latest custom driver.
