I'm afraid it's time to go TV shopping.
What I'm pretty sure you have is a defective panel, which is the actual screen, and a re[placement 42" screen would be more than the cost of a new TV.
But this is precisely why I urge anyone who buys a current technology HDTV to get an extended warranty. All of these TV's, regardless of whether it's plasma, LCD, or rear projection, have large and expensive assemblies that cannot be fixed, and must be replaced.
Definitely get an estimate from a tech, but be prepared for a real shocker.
Let me know if there's anything else I can do for you, and thanks for using JustAnswer!
Tami, there are a few things to consider, and LCD ma be the way to go.
Each technology has its advantages, of course, so let's see what might work for you.
Direct view LCD sets can be just wonderful. They are generally the most energy efficient. But unless you get one of the more expensive ones that have 120 Hz. (or higher) processing, you'll find that fast moving scenes will be blurry. Slow moving stuff or still frames will be very clear. Also, many direct view LCD's have a limited viewing angle, and the picture will deteriorate the farther off axis from the ideal viewing spot you get. Generally, screen sizes are limited to the mid 50 inches without getting really expensive. Choose models from Sony, Samsung, or Panasonic.
Plasma TV's generally don't have the image lag problem that LCD's do, and don't suffer from the viewing angle issue, but they can be real energy hogs, so if that's a concern, that might not be good for you. Also, they are much heavier than an LCD set, but there seem to be slightly larger screen sizes available than for LCD. If you think you will go with a plasma, choose Panasonic, but try to get a THX model, because the non THX models have an error in the color decoder that is, in my opinion, too annoying (but I'm more critical). Or choose a Samsung. They have issues, too, but if they bother you, they respond very well to a professional calibration.
And Vizio, while you've had problems with yours, is really becoming a big player in this field and have made substantial improvements. LG is not one of my favorites, for various reasons, but they do make an impressive product and have a reasonably good service support network.
Whatever you buy, be sure to get an extended warranty. This forum is replete with tales of woe about how the screen developed a defect and the set is out of warranty. The customer is left with a giant piece of e-Waste, which I'm afraid is what you have now.
Let me know if there's anything else I can do for you, and thanks for the Accept!