Computer game technical problem?

Hi! So I downloaded this game called Amnesia for the PC. It seemed to install fine and the game itself runs fine, but there is one problem. Every time the game is minimized to check something else, my mouse moves by itself all the way to the top left corner of my screen and WILL NOT move. There is no way for me to move it and do anything on my computer without restarting my computer. This only happens when I minimize the game while playing Amnesia. Any help on how to fix this would be much appreciated!