Fill colour, print preview

Hi,
I have problem with my Excel. When I change fill or font colour there is no effect, but if I check print preview or print document colours are there. On the screen main spreadsheet it shows black text and no fill colour. I tried to remove settings files (c:\program files\microsoft office\office11\xlstart and ...document and settings\application data\microsoft\excel\xlstart). Also in excel i tried to restore default settings by using detect and repair option in help menu.
Thank you for your help