This unit is a refurbished that was ordered from Amazon. Dell Optiplex 990 SFF Intel Core i5 Windows 10 At my 1st POST, I was presented by this message: "Alert! Hard Drive Fan Failure" "F1 to continue - F2 to Enter Setup" As I continue using by pressing F1, it took four days after the present problem occurs. New Problem: Power button blink then off for few seconds then blink again in loop. Please help me out.