Alienware 17 Windows 10 Monitor Stuck on lowest brightness

I have had my Alienware 17 for about 2 years.  Occasionally the brightness will randomly dim - no big deal, I just reset it. Last night I came back from dinner and it was dimmed, but in settings claimed to be at 100%. Night light setting is off.  I tried the FN keys and reinstalled drivers. Any adjustments to the brightness slider, functions keys, and laptop power saver optimizations are ignored. Other settings like resolutions or portrait/landscape can be changed successfully. Please help. Thanks in advance.