I have a Pavilion dv7-615ea product number LS089EA, running Windows 7.
When I switch my graphics from the inbuilt Intel HD graphics to the AMD Radeon HD graphics using the "Switchable Graphics" application, the screen goes black and stays black, even if I put it to sleep then wake it up again.
When this happens, I have started pressing Windows Key->Right->Enter as this shuts down the computer safely.
When I startup the laptop again, it uses the Radeon HD graphics card, but the resolution defaults to 640x480, however I can change it back up to 1600x900 when everything loads up.
Why should this be happening? It's really irritating.