Fan Won't Stop Running

Last night I used the key combination CTRl+B+WINDOWS+SHIFT to solve a problem with a frozen screen after sleep mode.   I wish I never had done that because now my PC fan keeps running for no reason.  The core temps are below 100 degrees Fahrenheit.

The airways are not blocked, the computer is not dusty.  Can anyone tell me how to stop the PC fan from running unnecessarily like this?