Can't launch TW2: app already running
So I've reinstalled Windows 8, updated it, reinstalled my drivers, et cetera, but somehow, I'm not able to play TW2 anymore.
When I installed it using Steam, I was able to open the launcher once, and play the game. But after I closed it and tried to open it again, the launcher wouldn't show up (but Task Manager showed that there was a process of the launcher). When clicking on 'Play' again, I get the message that Steam can't open TW2, because it's already running, except it isn't.
I found out that when I deleted the Appcache folder of Steam, the TW2 game folder in 'My Documents', and restarted my PC, I would "reset" this whole ordeal; begin able to open the launcher once and play the game, but after closing it I would have the same problem.
Does anyone have any idea what the problem might be?