System Instability?

Thanks in advance, my friends. *Please see specs below for detailed hardware configuration*

Ok, so about a few days ago, out of the clear blue sky, my PC decided to just... well... hang up. It would freeze whatever was on the screen, no blue screen of death, nor an entry into the event logs stating anything other than "Unexpected Shutdown." Due to the nature of it locking up, and not dumping, it makes it tricky in diagnosing yes? LOL...

However, there is something that I belive could be the culprit, but every shred of my body wishes it is not.

I own an Asus Maximus Formula Motherboard. It has little LED's for the CPU, Ram, NB/SB, for speed. In the bios, it is set to auto becuase my sytem is not overclocked, only stock bios settings. My long winded point is, the ram light is red. This means the voltage/frequency is set to the "insane" level in the AI overclock settings in the bios. However, upon maunally setting them to normal setting, the light won't go away.

About 9 months ago my PC had lightning take out the NIC. It was an onboard nic, and aside from the card failing, (The cable modem/router) was fine, except for the wan port, my PC was ok. About five months ago, it was hit again, that time taking my second onboard nic. Again, no fallout other than failed onboard nics. Could this be the anomilies seen down the road after being hit by lightning? Or is this an operating system issue? The red light on the mobo questions this however. But, using Asus PC probe, all voltages, and frequencies are fine. So, I dunno.

What I have done is switched the ram, still no go. Manually setting voltages that should have the light as green fails. No matter which sticks I run, or how many, same issue. I flashed the bios a few times. I believe these are connected, because the light did not appear until the locking up did.

Again, any help would be deeply appreciated. I fear its the mobo, but I don't have the $$ to buy another now.

Hardware Specs:
Windows Vista Ultimate 64-bit edition with SP1
CPU: Intel Core 2 Duo E8400 3.0GHZ
PSU: PC Power and Cooling: SLI Turbo 512 watts
Mobo: Asus Maximus Formula Intel X38 Chipset
Memory: G.Skill DDR-2 800MHZ Default timings
Graphics: BFG GeForce 8800 GTS OC 712MB Ram
Sound: SB Audigy 2 ZS
Linksys Wireless-G Speed Boost wireless card

Trust me, I feel the same way. But is there a way to know for sure? I know, I'm in the state of denial. LOL... But memtest perhaps? What would you, or others recommend? Again, thanks!

Almost forgot, I believe RMA is out of the question if the onboard nics have been fried by lightning right? Too bad I can't find the exact same motherboard anywhere. = ( The newer model is expensive, and these are tough financial times for me. What board would you, or others recommend as a replacement for my rig that is still on the market?

Bare in mind, I am not a gamer anymore, and I want stability. I could care less about overclocking. Again, thanks everyone! It is deeply appreciated. = )