I hit 4 to unlock core on my amd phenom 2 and now all i have is a blank screen

[jptbriers]

I have AND Phenom II 2555. Said motherboard M5A78L-MLX. I hit 4 to unlock core and now all I have is black screen.

 

[henydiah]

Standard checking :
- Swapped psu , or try other PSU
- Reset Clear Cmos,
- Reseat ram or try use another RAM and try use vga onboard first.
- Still blank you must check one by one in another pc - - all hardware not damage ?
- check PSU + motherboard + speaker motherboard + CPU , do you hear beep ? If no beep can be Reseat CPU
- still no beep , remove motherboard from case and try it out case.
- still had problem , rma your motherboard
Good luck brother