No POST on m3a79-t deluxe

[aoa2003]

Hello,

I bought a new 2TB samsung hardisc drive because my RAID0 setup (2x WD 150GB Velociraptor) was on the verge of being full.

Upon plugging in the new harddisc, I noticed right away that the usual 1 beep, was now 6 beeps, whereas the sound was "beep, beep-beep, beep-beep-beep", indicating to me the A20 gate on the mobo was defective.

I then went ahead and tried to see if it was a PSU issue, but even without the 3rd HDD, and without a dvd drive or anything, still the 6 short beeps. Also, even with a different keyboard, or no keyboard plugged in at all, no change at all. Also, the BIOS kept beeping beep-beep, beep-beep when I plugged out all memory, which leads me to believe the mobo itself isn't dead yet.

I then went ahead and did the 'hard' flash of the BIOS (removing all power, no CMOS chip, and the blue thingy near the PCIe slot off), only now to discover that it no longer beeps, while the harddiscs all run and I even hear the harddiscs working, as if they're booting Windows, yet I don't see anything.

My setup:
CPU:
AMD Phenom 9950BE @ 3gHz (Quad Core)

Mobo:
ASUS M3A79-T deluxe

HDD's
2x WD Velociraptor 150GB @ RAID0
SATA2 HD203WI (2TB) - the culprit

Keyboard/Mouse:
Microsoft Sidewinder X5 & X6 Gaming Keyboard/Mouse

PSU:
Chieftec CFT-750-14C (750W)

GPU:
Sapphire ATi Radeon HD4850X2

Memory:
8GB (4*2GB Corsair 5-5-5-15CL2)

What else can I do?

 

[aoa2003]

Update: looks like I didn't plug the blue thingy in properly, BIOS now again is back to the 'usual' 6 beeps, which started this mess.

Is there something I can do about the A20 gate, or does it mean I need to get a new mobo? Also, would it be wise to get a new PSU while I'm at it?

Edit for update 2:
When unplugging the memory again I get the constant 2 beeps again, and unplugging GPU gets me no beeps at all, rather then 1 long and 8 short beeps

Edit for update 3:
unplugging CPU nets me no beeps at all rather then 5 short beeps, and GPU fans don't even spin after a few seconds when the PC is turned on, while they do spin when they aren't powered on.

This leads me to believe the PSU may either be faulty or simply insufficient for all the components?