My PC suddenly stopped posting.

[jfem]

Hi,

My desktop PC suddenly stopped posting, only black screen in my display then I connected my monitor to the onboard video but still the same result. I tried to connect my monitor to a laptop to see if it is broken but it did display the screen on the laptop. What might be wrong with my PC? I've been using it for several months with no issues.

 

[jfem]

I opened it last week and recently this morning and the monitor displays windows for a second or more then back to black screen.