I have had this once or twice on my Dell laptop - Intel W8.1
I had no idea of the cause and it came and then went away - no issue for more than a year now. Your situation together with my experience strongly suggests to me an issue of software rather than hardware.
My fingers are crossed in the hope that it was a passing phase - perhaps you should cross your fingers too.
http://tinyurl.com/zkj6dv8
Good Luck...
July 2016