A suggestion that may work for you. Right near the start of the Game guide in the Game requirements section are links to DL Borderless Gaming. It will give you full screen/windowed. I have used it to see how it works and for anyone who prefers not seeing the taskbar while playing it solves the problem and I have the same issue Andy has with a small band of ~4 pixels unused on the left and right of the game window which doesn't bother me but Borderless Gaming does eliminate that.
After you've tried the other suggestions. Try that. These issues crop up occasionally and why is a mystery but I know there are people running the game with much higher resolutions than yours and running multiple screens. My machine uses an Intel Core i3 2130 @ 3.40GHz with 6.00GB Dual-Channel DDR3 @ 665MHz with a Samsung S22C300 (1920x1080@60Hz)
The latest version of Borderless Gaming can be found
HERE