I have Sony LCD Bravia TV KDL40ex400 and i kind of droped it, now when i turn on the tv i see shattered/cracked picture and when the tv if off it looks fine. Do i need to buy a new TV or can I just replace the backlight.
If you see a crack then its likely that you cracked the LCD panel (backlight is not the issue here) and at that point its best to buy a new TV, or replace the LCD panel.
For that TV it will be pretty close in price for the screen and labor opposed to just bying a new set. Maybe sell yours for parts to get something back, you may be able to get a $100 for it. Check with a few TV repair places to get a quote.