It's resolved (tagged this morning). I just wanted to make sure if anyone googles this, they know what I did to fix it.

Cheers

Replaced the RAM. Memtest isn't always correct. Only way to know for sure is to test with problem free RAM.

I'm really at my wits end with this problem.

I've tried almost everything I can think of. Things I have done:

- updated all drivers (and uninstalled apparently problematic ones)2
- uninstalled...