Sub UnprotectAllWorkSheets()
 Dim ws As Worksheet
 Dim myPassword As String

 If ActiveWorkbook Is Nothing Then Exit Sub

 myPassword = InputBox("Please enter your password" & vbCrLf & _
  "(Leave blank for no password)", "Enter Password")

 For Each ws In ThisWorkbook.Worksheets
  ws.Unprotect (myPassword)
 Next ws

End Sub