Computer screen: everything that used to be white now is teal color?

I just turned on my laptop after it being off for 5-6 days. Everything that used to be white (icons, text, background, screensaver) is now a teal blue color. It also looks as though there is a white shadow behind the black font (like what I'm typing now -- there is a teal background, black font, and a white shadowing on the black font). How do I change this to the standard white background? Is something seriously wrong with my laptop?Computer screen: everything that used to be white now is teal color?
Your monitor cable inside the laptop might be loose. My old laptop used to do something like this. Id press my fingers on both sides of the monitor at the bottom where the cover part is, and it would straighten out. Or Id just close the laptop and reopen it again and it would fix itself. But its probably the ribbon cable that goes up to the screen from the main part of the laptop. You have to feel around the base and see if that fixes it.