Thank you for the suggestions. The PC is very new and as such doesn't have much dust at all inside - the case is mesh on all sides except for the bottom, with a case fan, 3 fans on the GPU, a fan of the PSU, and a CPU cooler. Temperatures don't exceed 60 degrees when the issues occur, and after prolonged gameplay (when it was working) it would hover around 80 degrees at the very most.

I will check the health of D drive but as it's also been in use for only a week I doubt it will have deteriorated much. Thanks again.