Not easily ... you could possibly write an Excel VBA function to do this ... BUT ... Excel 97 and above have a condition format capability that will automatically format a cell based on a set of user entered rules
By selecting a cell or group of cells, format rules, can be applied under FORMAT Conditional Formatting.
setup a total column highlight the column select Conditional Formatting Set the first rule as: greater then 0 with Pattern fill Green Add a new rule and set to: Less then 0 with Pattern fill Red Add a new rule and set to: equal 0 (don't change any formats)
now the column of cells will follow whatever value exists in the cells; anything < 0 will turn the cell red 0 will be no color change > 0 will be Green