I have a 1999 big screen purgation mitsubishi tv

i have a 1999 big screen purgation mitsubishi tv and when i turn it on it go's to this ant-B and under that it would say stereo SQV and i can hear the show that is playing from the cable box but it dont show the picture but when i go to the menu for the tv and go to channel and it will show the picture for the tv in the box on the top right and when it was working the tv would come on and i would hit the input button four times to watch the tv but now it only has two input channels. i dont know how to fix it can u help me.thx