XPS 15 (9550) screen flickering then freezing completely

A few weeks ago, my XPS 15 started flickering for about 1 second and then would freeze completely, couldn't move my mouse and if there was any sound playing before it would stop. It normally happens right after I open the screen and it wakes up (doesn't happen on boot, just when it was sleeping) but occasionally happens while I'm using it. I've tried reinstalling the graphics drivers (both the 960M and the 530) and that hasn't made a difference.