Problem with power. TV shuts off and on.

Question

I tried shaking the TV a little bit and the power went back on and then shuts off in several minutes. I removed the cover of it and desturb the wirings gently with a none conductive wood and it went back on. So it appears to be working in proper but then it a few minutes it shuts off again. I can no longer open the back of the TV again and again since the TV set is extremely heavy. What should I do?