Used computer in the morning, left to run arrons and computer was off. Turn power on, no fans work, hard drive does not fire up, monitor displays 'no video input', only green LED lights up on mother board. I push on button but doesn't stay on. CPU fan moves a notch but stops. Replaced PSU and same thing. Is my mother board fried?

This is what I would recommend:
First, unplug the computer from the power outlet. Then re-plug it and try to start it. If nothing seems to work, but you have power (you can hear the fans start and hear the hard drive spin up, you can open the case and disconnect everything BUT the CPU, memory, and video. See if it starts. It should start up with video and give you an error saying something about no boot device. If this is the case, then start plugging things in starting with the hard drive.
If it doesn't work your power supply may be bad. If you have another to swap out, that's good. If you don't, then you really can't check it without a power supply checker.
If this doesn't work you are probably looking at a bad motherboard, bad CPU, or bad memory.

look on bios to see if detects the hard drive ...if does not boot to windows...the hard disk has no reason to go on ....and the issues could be many ....check the Ram memory if do not appear anything on screen at all ...and just runs the coolers and clicks without boot at all...in this case its the Ram memory ...so check it ...get it out ..put it back ...and remove the bios battery to force it see them again .....if it is booting until the operating system should appear ...and after that nothing ...reinstall ...
Also .....if there is anything written on the screen ..read carefully ..usually it will say whats wrong ...and advise in same issues..like replace hdd ...or files missing ...or blue screen error from memory issues..

Hi,
The monitor is not getting a video signal. This is probably an issue with your computer. It could be a memory, hard drive or motherboard issue.

Make sure you are getting power to the pc (fans running, hard drive spinning...etc). Then check your memory. Try switching memory slots, or try different memory.

Turn on computer and see if you hear any bios beeps.

Try a different hard drive if you have one.

Good luck,
Hank

For reasons yet to be determined, your computer is not talking to your monitor.

This could be the monitor cable came loose from the tower (this is our favorite, because it is such an easy repair), or something on the motherboard (that is, anything) that is not functioning and preventing your computer from starting.

Unplug the connecting cable, and plug it back in again, making sure that it is seated properly.

Do you hear any sounds besides the fans? You should be able to hear the faint clicking of a hard drive starting up also. If you hear this, the problem is not in the computer, but in the communication to the monitor.

Good luck
tony

Most likely your video card is broken. To check if the motherboard isnt broken either, I would suggest you test usb, sound, and other features of the motherboard.
 If your motherboard isnt broken then you have to buy a "pci-e graphics card" at your local store. Shouldnt cost much, about $40-70. Hope that helps.

seem power supply fault, because some times, it looks that power going on, it is not giving proper voltage to motherboard. check other power supply.

turn off the system remove all the cables from the back of the computer press and hold down the power button for 10 seconds now connect just the poer cable and try to tun on the system and as soon as it turns on tab the F8 key on the keyboard and then boot into last known good configuration

check both your power and video connections to the monitor, sounds more like a monitor power issue.
if the connections appear ok, but screen still blank, try connecting a known good working monitor from somewhere else and see if it works with your pc, if it does, your original monitor is faulty, if it doesn't, you have a pc video issue.

typical of external drives overheating.
i sell external case with fan at my store.

There could be a number of causes. Do you hear any beeps when the computer starts up? Try seating all the chips in the motherboard. That means, apply pressure to each individual chip on the motherboard with your finger or thumb. The goal is to make sure each chip is securely attached to the board. Sometimes, heat or new h/w installs partially "pop" some of the chips out of the motherboard - causing the circuitry to be disconnected...