Hi, I built my pc a couple years ago and in the last few months, rarely it started having issues booting completely and wouldn't make it to Windows, but when I restarted it once or twice, on those occasions, it made it to Windows, so I never got into the debugging mindset.
There was a power outage last week.
I woke up and remember a loud surge noise that may have come from my PC, not sure though.
Before the power outage though, coincidentally, I was playing Battlefield 4 online all night and remember someone chatted in game "how do you quit playing this game anyhow?"
Weird, the next time I went to turn it on this issue started.
I have the system somewhat isolated with a typical surge power strip, which didn't trip it's fuse during the outage.
Now the system will not boot, it only has time to display the first post code F3 (F6 with video card) then it powers down.
I managed to get it to boot a few days ago after unplugging and holding the pwr btn, resetting cmos, taking out the cell batt, etc.
I even played BF4 for hours without any issues again.
The mobo has blue pwr light always, fans, ssd, hard drives all power on during the 2-3 seconds power is on. Then it just turns itself off.
I never hear beeps from bios during the brief time the power is on. I doubt it's memory or motherboard or power supply otherwise how could do online gaming?
I appreciate any insight.

System specs
Mobo - EVGA x58 SLI le
Cpu- Nehalem 930 quad core i7
Ddr3 - 1600 Corsair 12 gb(3x4gb) & 6gb(3x2gb)
Graphics - 1 GeForce gtx 970 (also have a gtx 560 ti as backup)
Power- Thermaltake toughpower 850 W AP
Cpu fan- Cogage aluminum heatsink w 1 fan
Hard drive- Intel sata SSD 250gb

First, I couldn't adjust the voltages and timings since you have to get into bios and this mobo is turning off before bios starts.

I disassembled the pc to isolate mobo on a test bench with just the power supply, cpu and 1 ddr stick in each slot. I tried all ddr sticks no change.
I uploaded a video showing what happens.

Yeah, the issue went away for 1 day, now it's back with a vengeance.

Mixing your Memory most likely "Ddr3 - 1600 Corsair 12 gb(3x4gb) & 6gb(3x2gb)"
Remove the 6gb(3x2gb) Memory and (1) of your Ddr3 - 1600 Corsair 12 gb(3x4gb and retest.
Using only 2 Memory Sticks of the same make and model.

Already did, this isn't my first pc build issue.

dmcanfie
No, no, not the issue, all the memory is fine, it was there before this issue started.

I am in the process of replacing 8 Sticks of ECC memory that ran fine for over 3 years and running almost 7/24
So memory can go bad.

sorry didnt see this earlier. sounds like you already went barebones. then in that case your problem is one of those components. new PSU first. after that, honestly, I would consider upgradng your PC because it's not cost effective after that unless you are really on a budget. 
 

In reply to duenor, barebones, no disk of any kind connected, the post is the same, F3 》reset/off, F3 》 F6 》pwr off.
If I connect a disk it does the same thing.
If I add graphics card, same thing.

I'd suggest trying a different PSU just to rule it out.
 
Possibly might be a BIOS issue with that board, have you retried the same trick that worked before of removing the battery and discharging the board via the power button again? If you can get it to boot I'd immediately flash it to the latest BIOS, even if it is already using the latest BIOS it sounds like it may be getting corrupted somehow.
 
Could also be a contact on the board may just be failing in which case you can try the oven reflow trick, but I don't suggest it unless you're ready to toss the board anyway. Could even be the CPU... hard to really say. Are there any damaged pins in the CPU socket?

Where can I take CPU to have it tested? maybe give my local electronics store a call, like Frys electronics in Wilsonville, OR.

Yes, already used the lighted magnifyer to check that.
Man, just checked for upgrade, to skylake I5 and mobo bare bone combo and ddr4, this will run close to $500, maybe time to quit gaming :( as there aren't any 1366 mobo left for sale.

duenor, Hillsboro, Oregon area, that would be awsome!

duenor, I appreciate your time, any luck?

I hope you get well soon.
The 1st Gen Icore is what I have, guess so, it's a 1366 lga socket.
I may have some challenge making an adapter without the tools, but if there is one I can purchase, sure.