Custom Build - Not powering on - PSU button Stuck

Hi there,

So I am building a gaming rig for a friend of mine. I have a good amount of experience with computers and would consider myself at least of intermediate level, however this is the first time I've build a computer as complex at this type.

The case is a Cooler Master HAF X and the PSU is an Antec EarthWatts EA650 650W Continuous Power Supply.

When I tried powering the machine on there looks to be a surge of electricity for a second or two (even the some of the fans start to spin and the LED comes on) and then it just dies.

Another poroblem is the On/Off switch of the PSU is stuck in the On position. It will not click to the off position.

I tried sawpping the Power button wire with the Reset Button wire on the MotherBoard and the same thing happens so I'm assuming the problem is PSU related.

Having a look online, I saw that someone had said to check that the CPU fan is mounted correctly. I am almost 100 percent sure it is but I will recheck this the next time I am at the computer. I'm just wondering if there are any other possibilities to look into before I start looking to get a new PSU.

Regards.

What motherboard and CPU are you currently using?
I would suggest removing the components from the case and bench test.
Check that the correct amount of motherboard stand-offs are installed and in the right location.

-Place the motherboard outside the case (a piece of cardboard underneath or the motherboard box)
-Install CPU and heatsink
-Install one memory module
-If equipped with onboard graphics use this (graphics card removed)
-Connect PSU ATX connections to motherboard
-Momentarily short the two power pins to see if the PC will start.