My menu bar switched colors to a dark charcoal grey (the font is black) so reading it now is nearly impossible. It happend suddenly and without warning when I used my new scanner for the first time using a usb cable. (I hadn't yet set up wireless and was in a hurry to scan something.) How do I change my menu bar color back to the original (undo something, perhaps?) or at least to a light color that will contrast and make my menu bar readable again?