My Panasonic Viera 42 in. flat panel tv was accidentally knocked over. The screen looks okay and the sound is fine. The picture looks like a broken black mirror. Is the tv worth fixing or should I just dump it. (It is only 1 month old).

Sounds like a panel fault. Contact any service technician to confirm. If you wish to get some details; check the site linked here. Viewing it in "Mosaic" will make surf easy. Surf the site with patience. Pull up older posts. Surf the site with patience.
http://electronicshelponline.blogspot.com/
Screen-shots to defective LCD TV panel is given. You can compare it to that of your TV's, and can make sure.

Main board fault. Contact any service technician. Gopakumar Gopalan Google

Does it display channel numbers or other pictures when you press menu or other tools? If so, it's a problem with the TV's video inputs. If not, it's something wrong with the projection hardware, matrix, or power supply. Failing that, I recommend contacting Panasonic's support center, and keep any information you have on buying the TV handy. Good luck!

Go into menu of the TV and go to the setup for sound and pich internal speakers.

make sure your speaker to your sheron sound isnt to close to it .also if dvd player is the source then move away from tv will demagnatize the tv theres a magnet in them

It's called Cyan and it's sound like you are having a problem on your D-board. Look for capacitors bulging out and replace first if not then order D-board

The screen is cracked internally, there are glass layers under the top plastic film. You could get the screen replaced but might be as cheap to buy a new TV.

I just got a new panasonic Viera 42" plasma and when its on the picture sharpness is not that good and looks grey is this right

usually not very cost effective to replace the front screen. id say around 70% of what you paid for the tv.

Try this to get more information that will help diagnose the extent of the problem:

get a powerfull flash light
turn the tv on in the dark and point the flashlight right at the face of the screen and look for video..

make sure you have an active input or good channel selected..

if you see video where the flash lights then your cold cathode flourescant backlight is not working and this repairable at a reasonable price