weird issue

[nightstalkerr]

So me and a friend who built a computer over 10 times were building this rig. At the end everything was in place. The MoBo gave light, everything plugged in, all components in place and now. We tried to turn on the computer. It didn't start, so he said the RAM might not be in place correctly. So we put the 2x 4GB corsair Vengeance out of the MoBo and then putting it back in. BAM computer started and then turned off in a seconds. The screen wasn't plugged in yet so we didn't know if it said anything. Then we tried EVERYTHING. Weird part is that all the wires were correctly, all the MoBo lights were flashing. BUT there was no MoBo sound! I know it should be giving a beep when working. So we started from scratch. Same problem. Does anyone know if the MoBo is broken? EVERY component was fresh from their package, bought them a day ago. I'll also put the rig. Everything fits for a socket 1155.

EVGA 670GTX
Intel® Core™ i7-3770K
OCZ Fatal1ty 750W
Cooler Master CM690II Advanced +Window USB3.0
Samsung SH-222BB
ASUS P8H77-M PRO
Seagate ST2000DM001
Corsair 8 GB DDR3-1600 Kit

[Wikkr]

i get a similar problem with my PC since i replaced a few bits. It starts all the lights go on but the harddrive never spins up and it just sits there powered but doing nout. On other occasions it starts up for a few seconds then switches off for a few seconds before switching on to idle some more. Ive been led to beleive its either bad ram or a bad power source. Easiest way for you to tell is to swap the ram into another PC and see what happens.

[Hantzu]

The problem here is that it could be almost anything.

1) Confirm that your mother board DOES have a post boot noise and a speaker connected / on board. Some don't do this and use indicator lights instead.
2) Why would you start the computer without a monitor connected?

3) The CPU, Ram, Mother board, Video card, and Power Supply are all potential culprits here. Swap them out with known good parts one at a time.

[nightstalkerr]

The problem here is that it could be almost anything.

1) Confirm that your mother board DOES have a post boot noise and a speaker connected / on board. Some don't do this and use indicator lights instead.
2) Why would you start the computer without a monitor connected?

3) The CPU, Ram, Mother board, Video card, and Power Supply are all potential culprits here. Swap them out with known good parts one at a time.

You can still boot without a video card and the MoBo wouldnt start without a decent power supply.

[Yohassakura]

The motherboard doesn't always have a POST beep, some indicate just by its flashing LEDs. - Or maybe you just didn't plug the speaker in.

It could have shut back down (after fiddling with the RAM) because it didn't detect a display.

Couple of tests:

Make sure that you did actually wire the PSU to all of the components correctly
Try using only one RAM stick, then the other
Try using the onboard graphics card
Try using a different hdd
Try using a different PSU