Windows not starting up (black screen)

Hi,

My computer was working fine yesterday. I didn't shut it down, but hibernated it. And went to sleep before it was fully hibernated. When i woke up, it was still on and the desktop was black. I tried to restart, But the desktop is still black saying "no analog input". But the processor is still running with beep sound and lights on. I tried changing the cable, unplugging everything and pressing on the power button for few seconds but no use.

Thanks for any help.

Can you access safe mode?

no... i can't see anything... and keyboard doesn't seem to work

i thought it was the graphic card and replaced with working one. But it still doesn't work

When you turn on the computer do you see the BIOS screen or does it just show black screen from the start?