Acer 5920G black screen with ATI Mobility Radeon HD 4570


Dec 9, 2013
I am an owner of Acer 5920G. My Graphic card (nVidia GeForce 8600M GT) got burned.
As i have read from other users,these series of GPUs are getting burned very easily.Anyways!
I have also read that ATI Mobility Radeon HD 4570 is compatible to Acer 5920G
So I bought from ebay an ATI Mobility Radeon HD 4570.
Happily,I installed it on my laptop,but.......nothing happens,black screen!!
btw the motherboard seams to work fine,all leds are blinking and everything I hear works,but black screen!
As I know there are some custom BIOS for ATI Mobility Radeon HD 4570,but I can't find nothing!
Anyone has any idea what can I do to make my laptop work or any link to this custom BIOS update for ATI Mobility Radeon HD 4570??
Please help..... :(