Hello and welcome to Techspot.
I suspect you either have a psu problem or a mobo problem.
I take it you`re not getting any post beeps?
I suggest you start by disconnecting anything not required to boot your computer.
Just leave the mobo/cpu/psu/1 stick of ram/harddrive/graphics card.
If it`s still a no go, try another psu. If that doesn`t help, I`d say it`s probably your mobo that`s died.
Regards Howard :wave: :wave: