Black dots on the screen

Question

I have a Vizio flat screen. I bought it in November. The past couple of weeks, every once in a while, black dots (spots) appear on the screen. They are sporadic. They are not all the time. They go away briefly if I shut the TV off and turn it back on. They are not there if I switch to the Wii System or if I put a movie in. They are there, however, if I go from live TV to something that is on TIVO. Like I said, they are not there on a daily basis, but are very annoying.