Where does the start button wire go to the motherboard

there is proberly a electrical problem.try with a other PSU even you tested yours.manometers are not trustworthy.still got problem check all electrical wires to be seated firm and steady.
start check the wires.

Hello
It almost sounds like a mistake at the pc start switch and reboot switch.

Check that you have your pc start wires from the front start button of the case, in the correct spot on the motherboard.

Also remove the memory sticks and reseat them.

The green light on the motherboard is good it means your getting power from the power supply.

The start and reboot switch wiring can be tricky if one plug is in the wrong spot on the motherboard.

its most likely either your power button or power supply having an issue ensure the power buttons wires are all connected correctly as per the key for the motherboard and if its still not starting try using a different power supply if its still not working than its most likely a dead motherboard

Is the on/off button on the front of the computer-casing broken?
Take a volt-meter, and run a continuity-test.

Are the two wires from that button both properly connected to a pair of pins on the motherboard? If you disconnect the wires from those pins, and use a metal screwdriver to very briefly "short" the two pins, to simulate the pushing of the ON/OFF button, does the motherboard post? Do fans start to spin, or at least "twitch" a few degrees?

Have you tried a different power-supply?

Is there any lamp on the motherboard that lights-up anytime that
the power-supply is connected to AC power? Is that lamp on?

The best place to start will be the website for whomever manufactured the motherboard.

Seems like the start-button or the wire connected to it is broken instead of the mobo. Basically when you press the start button you short the 2 cables together. Try replacing any shabby looking parts of these 2 cables, and if here aren't any, try to replace as much of the cables as you can. Just try some basic copper-wire, preferrably insulated, and that should do the trick.

Make sure at the very least that the power cable is plugged into the wall (or a UPS) AND into the computer (and it is switched on).

Try power button, if nothing happens then...

Look inside the computer, make sure that you have wires running from the front part of the case (usually near the power button) to some pins on the motherboard...

If not then you need to figure out what wires are what and plug them onto the pins (use the motherboard manual to figure this out, or the internet; google your motherboard name + jumper settings)

Try power button again, if nothing then try another power supply.

Post back if you have any further problems.

Look in the manual there is a diagram and pin connections for each wire.

This link will give you a download of the manual. There were a few versions of the motherboard, but I hope the schematics didn't change.

Download Here

Does the system not even start up the power supply? That most likely means you've wired up your power button incorrectly. Also it could be possible that you're grounding the motherboard to the case. Make sure it is screwed onto the case correctly.