Color doesn't display -all black & white
 

When working on an account spreadsheet, no color will display. The negatives
are all black and white, not red, and the font and fill options won't change
from black and white. The choices are there, all the colors to select, the
icons, etc, but they don't work. I upgraded to 2007 one week ago. Anyone
know what I need to do to turn the color on?