Gigabyte GA-EP45-DS3L problems

I have a Gigabyte GA-EP45-DS3L motherboard. My PC sometimes starts up normally showing the GIGABYTE start up screen, but then my screen goes black. I can tell everything runs, as if I normally turned on the computer, but the screen is just pure black, I can't see what im moving or whats happening. How can I fix the Blackening effect?

PS- I can't get to my BIOS as well because the screen is still black.