Motherboard defective?

[Brocodile]

Hello, I am in a bit of a pickle.

 

I think my motherboard is defective, am I right? (I am no expert on this topic)
Here's the problem:

I've had my machine for about 4 years now without any upgrades, a friend built it for me. It worked fine until yesterday morning.
It won't start up anymore. 

The little LED on the mainboard is lit when the PSU is plugged in and turned on.

When i try to power on the machine the fans and fan-LEDs start spinning and light up for a split second before everything shuts off (for < .5 seconds)

even the power-led on the mainboard goes off, but after about half a second it lights up again, indicating the existence of power.

I've tried a different PSU, because that was my first impression that it was broken, but the problem remains.

unfortunately i don't have any spare parts to check what's really broken, is it the mainboard?

 

my stuff:

Asus Sabertooth z77

Eva GeForce GTX 680 2GB

Intel i7 3770K

Corsair Vengeance LP 4x4GB

BeQuiet BQT L8-cm-730

 

Thank you in advance for your help!

[JakeNTech]

Try shorting the pin on the mother board, take out all hardware at once aside from hdd and ram and cpu, if it works then put them back on by one to find out what is broken, if not then try a different motherboard

[Brocodile]

that's working, with hdd ram and cpu in place.

so its the graphics card?

 

EDIT

I put the gtx680 in, and it's still working.

I'm confused now

[Kapono]

Maybe a RAM Issue man, try replacing the RAM with weaker RAM. Before you do that, try this;

Trying putting all the RAM back In where It came, If It does not work then you have put the RAM In wrong, or your mobo can't support it... 

 

[JakeNTech]

If you can borrow some ram of a mate swap them out for yours,if that works then you can get new ram,and give the stuff from your mate back! If you have another GPU slot on the motherboard try that, if it is a ATX board, they have 7 slots for extra cards. Make sure your divers are up to date, if it comes down to it try to get a identical motherboard and try that, if its not identical you will need to have a new windows key to hand.

[JakeNTech]

It could also be your power supply is not powerful enough to power your system

[Brocodile]

But I've had this System for 4 years, nothing changed overnight but it wouldn't start up one morning.

could it just be the power switch of the case? I had to cram it up a bit to fit another case fan in..