Hi, I have a Toshiba Satellite L850 i5-3210m CPU laptop with dead HD7670m discrete graphics GPU. I don't get a video and when I connect the laptop to external screen I get "no video input" message. I've looked into reflowing GPU with heatgun on youtube as 1 possible repair solution. However, before disassembling the laptop I want to know if it is possible to disable discrete gfx chip so laptop will output video via integrate graphics chip. Can anyone tell me whether this is feasible? If yes, what keyboard combination do I use to do this? Thanks in advance for you help.