Private Sub Worksheet_SelectionChange(ByVal Target As Range)

End Sub

This function is found in the VBA editor when you doubleclick on a
sheet, ant then go to the right dropdownbox and chose SelectionChange


In this one you can have a check...

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim sRow, sCol as String

sRow = Target.Row
sCol = Target.Column

Then you can work with the string "sRow" to find out if it is 1 2 or 3

End Sub