Computer works but 'No Signal Input' on all monitors.

[Mit Parmar]

One day when I was playing a game and my computer suddenly shut down. I restarted few times and it worked well with display 2-3 times. Other than those 2-3 occasions it never started with something on display. It shows 'No Signal Input'. I can't even see BIOS screen.

-Monitor works fine, checked with two laptops.
-Cable is also fine...checked.
-Tried connecting monitor with both GPU and on-board port...no result.
-Unsure whether computer works or not, I can hear sounds of hardware, mouse glows but keyboard and USB drive lights are not glowing.
-Tried holding power button for 60 seconds...didn't work.

 

[Quinnsten]

try reseating the RAM if you have more than one stick try just using one stick if possible and try each stick of ram in each available port. Then try removing the Graphics card completely then just using the onboard graphics port.Aalso try unplugging everything internal that is not required to get a display for example any internal fans excluding the CPU(including cpu fan at last resort), hard drives and cd/dvd drives if you find it turns on plug in each internal device one by one powering on and off your computer until you find which is the issue. Also during this time only have your power cable and monitor plugged in (no usb's to rule out usbs, sound and network being an issue).

 

[HEXiT]

turn everything off at the wall.
turn on the monitor only.
wait till you see no signal.
turn the pc on at the wall and hit the power.

if the monitor jumps into standy the cpu is likely the problem.
if it stays on no signal its either the motherboard not being powered or the psu is giving no power.
if theres power in the gpu the no signal massage would disapear making me thing its motherboard/psu related

do the green to black jumper test on the psu to see if it can power a fan. if so its likely the motherboard.