Im Back With a New Problem :D

Going to start it off with whats been happening so far. So From last night til about 4 am this morning my computer would not post. What it would do is this, either scenario 1: Start for 10 Seconds, turn off for 5, Turn back on and keep running but black monitor / No Leds going to my videocard showing its getting signal, Also no leds on my RAM slots. Or Scenario 2:It would boot, but thus far it did nothing Same as 1 but no restart it would just run the fans and led lights minus the ones on the Vid card and Ram slots. I tried about everything to post then right when i was about to say forget it, I closed up the case sat it up right and for no reason what soever I DID NOTHING. It posted, i'm like sweet ok The blue light on my 9800 gx2 comes on and on my RAM slots. It boots up I install windows etc. So then I go to work at 10am get back at 2pm. Now i'm like yay i get to mess around with my new build etc. But INSTEAD when i turn it on it flickers for 1 sec then goes right back off so i'm like uhhhhhhhhhhhhhhhhhh.... I tinker around reset the cpu and it now goes back to the ol scenario 1 & 2. I'm completely stumped i have an idea of what the problem via hardware but not sure. This one is really tricky...... Btw i just RMAD and got a new mobo the one i'm using the last one had a power switch doa.

What i'm using

Power & Cooling S75QB 750W ATX12V

XFX GeForce 9800 GX2 Xtreme 1GB PCIe

G.SKILL 3GB (3 x 1GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Triple Channel Kit Desktop Memory Model F3-12800CL9T-3GBNQ

Intel Core i7-920 2.66Ghz 8M LGA1366 CPU

Asus P6T-Deluxe Intel X58 Socket LGA1366

Western Digital Caviar SE16 WD6400AAKS 640GB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive - OEM

XCLIO Windtunnel Fully Black Finish 1.0 mm SECC Chassis ATX Full Tower Computer Case


Can anyone think of WHATS GOING ON... i'm completely in the dark.

Thanks for any help