Alternating color of lines

Hi there!

I need to write a macro in order to format a worksheet so that the line colors are alternating (ex: grey and white), for easy reading after print. However, the file will be change constantly by people that don't care much about formating colors....So I want to assing this macro to a button (I know how to do this part!)

I tried, but it didn't compile, and I couldn't get it right...

NOTE: The selection should start not from the begining (ex: line 4) and be applied until it meets an empty field in the A column.

Here is what it looked like.... I can do with a brand new code, but I would learn better if someone can tell me what I did wrong!

Dim Count As Integer, End As Integer
Count = 4

Do
Rows("Count:Count").Select
Selection.Interior.ColorIndex = 15
Count = Count + 2
Loop Until IsEmpty("ACount")

End = 5
Do
Rows("End:End").Select
Selection.Interior.ColorIndex = xlNone
End = End + 2
Loop Until Count < End

THANX!