hide/unhide protected cell base on value

[blacksmith]

Hi Guru,

Got some problem here, how can i reverse the code below to unhide the row. or help me incorporate w/in one botton = hide/unhide for the below code. opppsss, before i forget, what the selected range to be hide/unhide is protected since some cell and populated w/ formula?

Sheets("Summary").Select
Range("O19:O39").Select
For Each Cell In Selection
    If Cell = 0 Then
        Range(Cell.Address).EntireRow.Hidden = True
    End If
Next

i try to insert below code but doesn't work, only the hide rud. also, is it possible to run it once cell was change? im currently using the code w/ botton to execute the code.

Else
   Range(Cell.Address).EntireRow.Hidden = False

many thanks