Blackscreen when fullscreened. (Sorry if I'm posting in the wrong place)

When I open the game in full-screen, it goes black. The game is still interactable and the WoW cursor is actually showing. When I alt-tab I get a glimse of the game. So through alt-tabbing and trying to set it to windowed, it finally worked. However I still cannot play in fullscreen.

This happened after I updated Windows, so I'm sure it has nothing to do with the game files itself. I'm here to ask if anyone knows a fix or has had the same problem?

Thank you in advance