Dead mobo

[vpu3]

one night i left my computer running to downloads a big file. i was at work came back home i notice my computer was turn off. So i turn it back on everything was fine then i shut back off i tried to turn it back on the power at all. i tried a different psu but still nothing. but this mobo was used anyways. so i assume the mobo died. what do u guys think?

 

[Nodsu]

Did you plug it in? Did you remember to flip the power switch on the PSU? Do you have the power button wire connected?

 

[vpu3]

yes everything is connected sometimes the computer work sometimes it does not. maybe a loose connection on the mobo