I encountered a similar "problem" if you will today. After hacking a bit this is what I ended up with.
' Run macro automaticly every time the Worksheet is changed
Private Sub Worksheet_Change(ByVal Target As Range)
' Define the range we wish to check against for x'es and v's.
Set ColorMagic = Range("C5:C24")
' Start checking each cell in the target range named ColorMagic for v's, x'es and nothings
For Each Cell in ColorMagic
If Cell.Value = "x" Then ' Color it red
Range("A" + CStr(Cell.Row) + ":C" + CStr(Cell.Row)).Interior.ColorIndex = 3
ElseIf Cell.Value = "v" Then ' Color it green
Range("A" + CStr(Cell.Row) + ":C" + CStr(Cell.Row)).Interior.ColorIndex = 4
else ' Remove all color
Range("A" + CStr(Cell.Row) + ":C" + CStr(Cell.Row)).Interior.ColorIndex = xlNone
Now... This will change the cells in the range A to C on the checked row to Red if the value of the column C equals x, Green if it equals v and no color if it's anything else. This can be modified quite easily by adjusting the ranges and so fourth.
Hope this is of use to someone. :)