How are you hooking up your camera? What output jacks on the camera are you using and with what cable? Do you have the camera in "Playback" or "VTR" mode? What about the TV? Do you have it on the correct "Input"? If you "Play" the tape in the camera, you should be able to see footage through the viewfinder. If you see the footage this way, then all is fine and it's just a matter of using the correct setups and connections.
Over the holidays, I went to show my parents some video I shot of our son's Christmas program, by hooking my Panasonic DV101 up to their TV. There were several lines across the screen that look live garbled pixels. I thought maybe the heads are dirty and looked at my owner's manual. It says that the heads should rarely if ever need cleaning. What could the problem be? Is my camcorder or the footage of my son's program toast?