Mine is randomly hanging up. It's either bad memory sticks, hard drives failing (again). Or, it's finally time to splurge on a new system and retire this one after 12 years of loyal service.
I had a semi-similar issue where games would randomly "freeze" - or rather, you could still hear stuff happening and reacting to key inputs, but the screen was completely frozen. Turns out slightly lowering the clock speed of my GPU basically fixed the issue. I wonder if something similar would be able to extend the life of your GPU too.
Thanks for the well intentions, but so far I know it's not the disks, I changed them last year. I run Linux Mint, so I use other tools to monitor the disks and memory. I actually suspect it's the graphics card getting funky because running things in software render mode solves the random hang ups.