Computer will get to Start-up then Shut down?

[vashanime04]

Hi i needed some help diagnosing the problem on a Pc that is Homebuilt. I built this about Two years ago but about 2 months back it started having some problems. It went from recognizing all 6Gbs of ram (3-2Gb sticks) to me noticing that it only recognized one. I had to take out the extra sticks to get it to run. When i tried putting them back in or switching them with the known good one it would boot then shut off. Now i recently turned off my computer and now when i went to turn it on to use it. It will only go to the start up or Welcome Screen in Vista then Shut down. However the Shut down is like a complete power off.
I have a feeling its the memory thats gone bad(or overheated) but it could be the Pws. Any help is appreciated so i can get it up and running.


Whats in the Case.
Intel Core I-7 920
G-Skill 6gb 3-2Gb sticks
GIGABYTE GA-EX58-UD3R LGA 1366 Intel X58 ATX Intel Motherboard
CORSAIR CMPSU-750TX
SAPPHIRE 100251SR Radeon HD 4870 X2
Os- Vista Ultimate

 

[zero888]

If possible replace the memory with different ones and see if that makes a difference. If not, then it could be 1 of 3 things, your mobo, cpu, or psu.

 

[vashanime04]

Finally got it up and running.