I have looked in device manager and have no conflicts or yellow exclamation icons.
My monitor is an Iiyama 17" only 5 months old so I don't think that is the problem. I had changed my refresh rate to 75Hz 2 weeks ago and think that that wss the time it started. I have since changed back. The screen is only slightly bigger when the monitor powers back up but big enough to have the start icon half-submerged.