I disconnected every thing from the comcast cable box to my tv, unplugged the tv from the power outlet. I let it set for about 5 minutes then plugged power cord for tv back in. Still disconnected from cable box. Using the source button on the tv or the imput button on remote I can not get to the screen to pick connect to cable or antenna. The tv is an Olevia 720p (yes its old, but still works great). Then I connected the indoor antenna to coaxial imput marked ANT HD got the same issue. What am I doing wrong?