Okay this is... Ever weirder, Julusp.
I've done as you've instructed, and I realized there was only a single change:
After updating the processes mom.exe and ccc.exe were now running. They weren't killed, they were added.
And those are processes from the Catalyst Control Center, ATI's graphics driver thingy?

So for whatever reason, the CCC isn't booting up when I turn the computer off, and it needs to be active to run XIV smoothly. Now I have no idea what is up anymore.