Picture too big for screen - Sony KP-57HW40 57" Rear Projection Television

Try grabbing your remote press the menu button go to picture and see if its on zoom insted of normal or stretch

Sounds like your cable box is zoomed in, I run into this a lot when running service calls. On most cable provider's remotes there is an 'aspect' button next to or around the '0'. Try that and see if it helps you out at all :)

This is especially common with Phillips/Magnavox - A foggy image usually suggests that the coolant in the picture tube(s) (1or all 3) has become discolored and needs to be replaced. The only way to check this is to look directly into the crt faces (disassembly required) to see the condition of the fluid (coolant).
It's a relatively big job that shops charge between $300-400 - Get an estimate. See link for Kit
http://www.tvrepairworld.com/crt_coolant

Try VIEW MODE button on the remote or ZOOM button on the remote from cable box.

Ur convergence is dead,go to ebay.com buy the convergence repair kit.Find out ur make and models,and manufactures of ur TV buy it.
All big projection DLP have this prob. one time or other every manufactures,Sony,Samsung,RCA,many others.

Look for button on remote labeled size,aspect ,format or zoom. You can change the picture size to your liking. Different channels are broadcast in diffrent formats.

you need to go into the picture menu, and play around with the screen size options.

GO TO MENU VIDEO SETTINGS AND RESET TO FULL FORMAT SETTING , GO TO JVC.COM AND DOWNLOAD THE OWNERS MANUAL GUIDE ,

IF THIS IS A LCD---TURN ON, AS NORMAL AND HAVE A SIGNAL INPUT,,CABLE ,SATELLITE CONNECTED TO THE ANTENNA INPUT .MAKE SURE YOU HEAR SOUND.. HOLD A LIGHT (THE BRIGHTER THE BETTER) IN FRONT OF THE THE SCREEN ('BOUT 3 INCHES)--IF YOU SEE A DIM PICTURE---BAD SCREEN AND THATS BIG BUCKS---IF STILL NO PICTURE--CIRCUIT BOARDS AND USUALLY THATS BIG BUCKS!! GOOD LUCK