My mobo an issue?

So my computer decided to just freeze up on me and give me no warnings. In fact, it does this every single time within a hour or 2 of boot up. It does this and now I've completely lost my onboard nic. Can't load drivers because windows doesn't detect it and says there isn't even one. Wondering if my GA-Z68X-UD3H-B3(1.3 as it says on the board, @bios says 1.0) So my troubleshooting steps so far:

Checked cooling: everything is in reg range: gpu, cpu.
Ran a MSE full scan: nothing. Ran a Windows Defender Offline Tool Full scan: nothing.
Ran chkdsk: no problems.
Ran sfc /scannow: nothing.
Checked power supply(800w) with a tester: no problems.
Changed ram from a working PC: no problems. Even did memtestx86: nothing. Switched them around all 4 slots.
Changed video card from HD6950 to Nvidia 470GTX. No difference.
Unplugged all usbs except for mouse/keybo: Nothing. Even just went with a PS/2 keybo: no difference.
Even changed bios. Went higher, then lower. Nothing changed.

Things I haven't been able to truly test. CPU(2500k). Don't exactly have another to test. My motherboard.

I'm thinking the mobo is bad because heck, even the NIC isn't even working. Nothing is physically wrong though.

Anyone know of anything else I can check/do? It doesn't matter if the comp is Idle or actually in a game/prog./internet.