Why does my computer screen turn either green or pink?

Why, since I have signed up for Yahoo messenger, is my screen green when I turn on the computer. Is normal in

• I signed up for Yahoo Messenger and since that time, whenever I turn on the computer, my screen is green. It does return to its normal colors within a few minutes. Is somethimg wrong?

• Answer:

  I find that remarkable! And I really wonder if the green IS a direct result of your signing up for YM, or perhaps related to something quite different (perhaps around the same time as your Yahoo signup) ? Anyway, without knowing more detail, I'd say probably there IS "something wrong", but as long as things DO return to normal each time perhaps don't worry too much. (I'd like to know more about this "green" though. I take it this occurs only when you boot the PC ? And at what point of the process... does normal text still show, or is screen just 100% green ?)