This worksheet event macro forces a comment in Cell B9:
Dim got_here As Boolean
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Set b9 = Range("B9")
If Intersect(Target, b9) Is Nothing Then
If got_here Then
If b9.Comment Is Nothing Then
b9.Select
Else
got_here = False
End If
End If
Else
got_here = True
End If
End Sub
Because it is worksheet code, it is very easy to install and use:
1. right-click the tab name near the bottom of the window
2. select View Code - this brings up a VBE window
3. paste the stuff in and close the VBE window
If you save the workbook, the macro will be saved with it.
To remove the macro:
1. bring up the VBE windows as above
2. clear the code out
3. close the VBE window
To learn more about macros in general, see:
http://www.mvps.org/dmcritchie/excel/getstarted.htm
To learn more about Event Macros (worksheet code), see:
http://www.mvps.org/dmcritchie/excel/event.htm