Electronic Components/sony tv grainy picture
have sony KDL46S2010 tv with a grainy picture
There can be a few issues going on here, and unfortunately, I don't have enough information to help, but I can give you some ideas.
Firstly, I don't know if this TV is new to your entertainment system. If it's new - if you are replacing something smaller, it's possible that the signal you are putting into the TV is of insufficient resolution to display clearly. If this is a new TV in your system, and larger than a previous set, it might be that you are just now seeing the difference in the quality of your signal.
It looks like your set is capable of 720P resolution, and a 46" set is about the maximum size for good display at this resolution - you could be getting a little bit of graininess just because you are at that upper limit. 1080P or I would be a better choice for larger sets.
Also, a TV like this, displaying older VHS or even non HD DVDs will show them at an apparently lower quality than an older, smaller set. It's much like taking a photograph with a digital camera and trying to enlarge it. You will reach a limit where the size cannot be increased without damaging the resolution. This is called pixelation.
If this is a new problem, and you can't see things as well as you were able to on the same set, it's possible that the resolution settings have been changed on the TV or the source. These are usually accessible in the set-up menus.
Sorry I can't be of more help - there wasn't a great deal of information to go on.