I'm guessing you mean fill with colour.. If you right click on the cell and click format cells, you should open a window where one of the tabs is fill. Or highlight it and fill from bar at top, button next to change font colour. However this is in Excel 2007.
The fill facility just does not work anymore and in saved files where I have used it , all the fill has gone tfrom hose cells where I had used it previously inmy saved files. How do I get it to work again