[CRASH] Random black screen 'flashes' occur 2-5 times per game

I've been having this problem for around a year now and after trying everything I possibly could to solve it to my knowledge I've decided to report it.

Essentially, several times per game, the screen will randomly turn black for anywhere between 0.5-3 seconds. I assumed this was an issue with my graphics card so I've already gone through the clean install steps with drivers, I've completely taken apart and reassembled my PC, and essentially every other logical thing to do with a graphics issue.

This happens every game but I've noticed that it happens more frequently when the shadows are turned up to very high.

These are my relevant system specs:

NVIDIA GeForce GTX 555 (with most current stable driver running on a clean install) 8GB RAM Intel i7-3770 @ 3.4 GHz Dell 21.5" monitor

If anybody has any insight on how to fix this I would greatly appreciate it.