Hello,
In what way isn't the code working? Do you get an error or does it just appear not to do anything?

If it doesn't seem to be doing anything, make sure that:
(1) the code is in the ThisWorkbook class module of the workbook
(2) macros are enabled
(3) events are enabled (type Application.EnableEvents=True into the immediate window)

If it gives you a runtime error then please give us the details of the error. It could be the case that
(1) a sheet called Sheet1 doesn't exist
(2) Sheet1 is protected.

Hope that helps...