Emerson tv wont turn on

I have an Emereson EWC1902 tv/vcr combo. It worked fine until last night when the picture turned black and white, which seemed like a cable problem. After moving around the coax cable, I tried tapping on the top of the tv. When I did the picture cut out to a small blue spot in the middle of the screen. I turned the tv off and tried to unplug it. Now it does not do anything but make a low whistling/humming noise and will not turn on. Can anyone help me please?