could be damaged video drivers..a bad gpu or a power supply that the 12v leg is failing. if your mb has onboard video turn off the pc. pull the gpu and boot into safe mode and remove the old video driver and install the newest driver. if the system with newest drivers install still hangs/crashes. try another gpu.
Thank you for the help. My MB does not have onboard video. I have in the past done an uninstall/install of the latest driver, but it did not change anything. I did not boot in safe mode to uninstall, should I try it that way?