Don't know a whole lot about this but simple things like is Crossfire selected in the drivers would be a good place to start. Does this happen in just one game or in a selection ? If its a single game google to see if there are issues with Crossfire support for that game.
Did it work before ok but the Driver update has screwed it up ? If so roll back the driver and see if its ok again. If it is leave the drivers on the old ones.
What's your OS ?
Also open CCC>Information center and select "Graphic hardware" tab,you have to see either "Primary adapter" and "Linked adapter" or "Primary adapter" and "Disabled adapter",which one is available there ?
Also what do you mean the game stop after playing ? do they crash ? do they give any error ?