Toshiba Satellite L305D-S5934 laptop screen black

I have trying to switch out the ram and worked for three tests of restart to see how the screen responded and on the fourth restart the laptop the screen went black. I connect the laptop through vga cord to a different monitor while holding Fn8 and couldnt see anything.

is it the graphic card? and if so how do i know which one to buy??


http://www.cnet.com/laptops/toshiba-...-33884904.html

Graphics ProcessorATI Radeon 3100 HyperMemory