I've been using Windows 8.1 for a few weeks now, but since yesterday the mouse cursor stopped being locked to some games (Watch_Dogs, Dead Island). Watch_Dogs worked just fine two days ago, didn't try Dead Island before. Other games like Loadout work just fine.
I didn't install any new drivers (even tried reinstalling my graphics drivers though).
I have a Nvidia GTX 770, but as I already said. I installed the new driver a few days ago when it came out and Watch_Dogs worked just fine with them.