Television and Home Theater

My picture on my Toshiba 55x70, is for want of a better explanation cutting off the top of the picture, its like the screen is sized wrong like a computer monitor that needs resized --- any suggestions on how to correct this?

I have a RCA model F38310 HD TV with a build in DirecTV reciever. I want to add a DVR or TiVo type device. Can this be done in conjunction with the built in DirecTV reciever, or will I need to get a new reciever that can then be wired to the DVR and bypass the built in one???
Thanks,
Ted

I'm having a problem. I just moved and tried to set-up my tv with new cable installation and this is what happened: I went to set-up and must have pushed something I should not have because when I go to a channel I get a big solid black box that nearly fills the screen. I have no idea what to do or how to get rid of it. Unfortunately, I do not have the manual that came with the set.