Not sure how to troubleshoot this issue. Screen would freeze up and display those symbols along with discoloration. It BSOD "DPC Watchdog Violation". Event manager says graphics driver was corrupt. Have had issues with software in the past so reformatted and installed clean OS along with latest drivers. Same thing occurred. The only correlation is that Overwatch was open all the times this has been happening but that is a game I play fairly often so not sure what to blame or how to fix.