I've got a feeling it's my 5700XT if it is indeed hardware. I've only had issues with it since I bought it, but i'm unfortunately not in a position to be able to sell it and buy a new one at the moment.
I've gone through the DDU process multiple times and it hasn't fixed anything for me. Most annoying issue I keep getting with the card is that it believes my second screen (which is 1080p) is some stupid 480p resolution, every time the PC starts it resets to that res and I have to unplug the monitor and replug to fix it.
I generally use AVG, although it's now not installed (and the issue was still there albeit a bit better.
I haven't been able to test it today but will do this evening when home from work. Will see if the issue appears again, and will try and decipher what, if anything, causes it.