GA X58A UD3R wont post

[Lizserver]

Hiya There,

I finished building my first pc after months of savings, when I tried to connect to a monitor the system wouldn't post and I am quite sure that I haven't  made any mistakes when installing the hardware because everything seem to be working fine. I dont know if  I Am missing something, or if its a problem with the motherboard?

config-
Intel i7-950 Quad-Core Processor (3.06 GHz, 8MB Cache, Socket 1366)
Corsair XMS3 - Memory - 8 GB : 2 x 4 GB - DIMM 240-pin - DDR3 - 1333 MHz / PC3-10666 - CL9 - 1.6 V - unbuffered - non-ECC
Gigabyte GV-R465OC-1GI Radeon HD 4650 Graphics Card (1GB, ATX, DVI-I)
LG BH10LS30.AUAR10B 10x Internal BDRW Retail Kit
Coolermaster HAF 922 Mid Tower Chassis
CorsairR CWCH50-1 Water Cooler
Gigabyte SKT-1366 GA-X58A-UD3R Motherboard
Samsung F3 HD103SJ 1TB internal Hard Drive SATAII 32MB Cache 7200RPM – OEM
Colors-IT 650w Titan 12CM Neon Power Supply

[Dark Mantis]

Hi and welcome to the Gigabyte Forum.

You don't state exactly what memory kit you have but that would be my first supect as I notice that you have a Dual Channel kit in a Triple Channel motherboard. It might be possible to get this to work but it is not exactly recommended.

Secondly have you made sure all the power cables are connected to the motherboard including the EATX 12V near the CPU?

[Lizserver]

Thank you for the quick reply

I didn't connect the atx 12v near the CPU because it has 5 gnd pins and 3 12v pins and I was afraid in case would cause any damage to the board.
I would like to know how should I connect the pins because on the manual says that 4 gnd pins and 4 12v pins.
Cheers 

[Dark Mantis]

Well I can understand your concern as it should be four ground wires and four power wires(+12V). The motherboard won't boot without these connections so you are going to have to check them out. Firstly make sure that you have the right cables for the connectors.

What make/model of PSU are you using?

[Lizserver]

Colors-IT 650w Titan 12CM Neon Power Supply

[Dark Mantis]

Well not being funny but I would ditch that thing as soon as possible as apart from your problem with the wiring being wrong the general concensus of opinion on the web is that they are less than reliable to be brutally honest. If it is still working now I think you should count yourself lucky and replace it with a proper PSU like Seasonic or Corsair or Gigabyte. Try and get a single 12V rail type of at least 650W.