Macro to format a sheet
 

I have data that is exported to Excel from another system. The data is not
formatted and I need to format it according to a code which is in a specific
Col. (Col G). The Code is something like this example TWP = Title, Font
Color White and Fill Color Purple. For a Title the format must be only in
the cell in Col A. Then for a Total the whole row (Col A to F) must be
formated in a font color and a fill Color depending on code.

I need to write macro commands to do this formatting for me but I don't know
how to write a loop in Excel to read all the rows of my spreadsheet until the
last row of data (no of rows can change) and format then according to the
code in Col G.

Can somebody help me?