The problem can be caused by the high contrast setting. There's
information in the Excel FAQs he

http://www.contextures.com/xlfaqApp.html#Fill



Judy wrote:
When I try to use fill color on a spreadsheet, it doesn't show on the
screen. When I do a print preview, or print the colors are there. Also
when I type my letters in black there seems to be a "shadow of a color"
behind them as I type. What's going on? How can I fix these two problems??


--
Debra Dalgleish
Excel FAQ, Tips & Book List
http://www.contextures.com/tiptech.html