problem with game minimiseing and then going full screen.

[Risen]

my problem with the game is that it keeps going in and out of fullscreen mode to the point that the game is unplayable and changing the graphics doesnt help..... when it does this there is a notice that comes up for my graphics card that says that it stopped working and then recovered.... is this a computer problem or a game problem? ive tried downloading the game from both the oficial site and steam.... i curently have the steam download. i cant even get into the game long enogh to submit a bug ticket....if anyone knows anything about this please reply.... help would realy be apreciated. thanks