Putting the following code in the worksheet's Selection Change event will
color the active cell dark red, with a white font. Setting the remaining
cells to standard background and foreground colors.
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
With ActiveSheet.Cells.Interior
.ColorIndex = xlNone
End With
ActiveSheet.Cells.Font.ColorIndex = vbBlack
With Selection.Interior
.ColorIndex = 9
.Pattern = xlSolid
End With