if you do not name the cell but go through the conditional formatting selection from the menu, select "formula is" then select the sheet (tab) you want the cell to look at and then select the cell you want to control the format (colour) and type "=1" after the cell reference automatically entered ..... be aware of these points
the arrow keys will not work as you expect in the formula bar
the range selected must be a single cell reference style ..... if you get an entry like "A1:C1" ..... you must delete the ":C1" part before typing "=1" or it will not work
hope this helps
The Gunslinger