Step 1:  DON’T PANIC AND START HITTING ALL KINDS OF BUTTONS OR JUST SHUT OFF YOUR MACHINE.
Step 2:  Let it sit for 5-10 minutes and see if it works itself out of the problem.
Step 3:   If the machine doesn’t work itself out of the problem after sitting for at least 10 minutes, turn the computer off, wait 2 minutes and turn the computer back on.