You may have your printing color setup in monochromatic (Black and white). Change this by going into your printer options (found in Control Panel) and set this to color.
It is most probably that the software you are using to print is set to only print in black and white or greyscale. If this is not the case check the print settings in the operating system are correct and you have the correct drivers installed.
Take a look at your printer driver, and see if it is set to color or black and white - often this is a setting we often miss. Some programs (power point) have a separate setting where it displays B&W as well.
