help,my home is filled with broken?

hi can anyone shed any light on the problem with my LG tv.turns on fine no problem,but i dont get any sound or channels? But if i hold one of the channel buttons in i get the sound and picure fine.as you can gather i dont wnt to sit there alnight holding a button in,it would be a shame to throw this tv away as it is in good as new condition,please help :(