PSU to blame?

[Scionix]

Hey guys, just installed some upgarades, and afterwards my PC would boot up, run for about twenty seconds, then just shut off. I'm pretty sure this is because of my PSU just not being up to the job, but I wanted to make sure it's not something else before I spring for a new PSU.

Here are my specs:

PSU: Newegg.com - CORSAIR CMPSU-620HX 620W ATX12V v2.2 and EPS12V 2.91 SLI Certified CrossFire Ready 80 PLUS Certified Modular Active PFC Power Supply - Power Supplies

Nvidia 750i Mobo
Two 8800gt's in SLI
Intel Q6600 Quad-Core
8Gb Corsair Dominator RAM

Any replies would be awesome.

EDIT: Shutting down fixed, now getting a hard drive failure (bios won't recognize either of my IDE hard drives)

 

[kmote]

That power supply should be enough. Try running memtest, that should do two things 1) rule out OS/ software issue 2) rule out RAM

 

[Scionix]

That power supply should be enough. Try running memtest, that should do two things 1) rule out OS/ software issue 2) rule out RAM

Er, how does one run memtest? >.>

EDIT: Switched out ram, no luck. My processor/motherboard are also freshly put in, so that also might be an issue.

Well, good news and bad news. Good news is, I've fixed the shutting down (I think my CPU fan was loose). Bad news is, now the motherboard won't recognize my hard drives in the SATA slots

Any ideas? The 750i has this thing where you can go into BIOS and hit enter in the IDE slot your HD is in and it will detect it, but It won't recognize either of my HD's >.>

Any ideas?

 

[CrazeD]

Perhaps the fact that it's not IDE?