Problems runing Amnesia

[tshansen]

Just downloaded Amnesia from Impulse and Steam and get the same problem both places.
I can start up the game without any problem and can zoom around and look around at the surroundings in the game. But when trying to click with the mouse the game shortly change to the desktop and back. This problems continue and eventually the game crash/freeze.
I have tried the options mentioned in the Amnesia troubleshooting guide without any luck.
The game runs on a laptop computer with a ATI Mobility Radeon HD 4650 graphic card onboard with Windows 7
Any suggestion how to solve the problem?