Why does my nikon D80 highlight certain parts of the photo?

Ill take a photo and some areas are brighter than others.
I don't have a filter on it, so i know its not that.
What can i try looking for to see if i can change
it back to normal?

If on playback parts of the image are flashing ('blinkies') then this is telling you that those parts of the image are blown out (ie white with no detail).To turn off the blinkies, you need to use the multi selector button to the right of the LCD screen (on the back). I'm not sure whether you press it up/down or left/right as I have a D100 and a D300 and both are different. Anyway, one of the directions will scroll you to the next/previous image, the other will give you various image viewing options, including viewing with/without blinkies.

Look in your user manual on pages 63 and 64 to setup your photo information display

If you are getting a lot of "blinkies", that means that you are overexposing your images. You need to correct this before you shut off that feature.