Private Sub Workbook_Open()
Dim FFold As String
Dim FName As String
Dim FPath As String
Dim Exists As Boolean
Dim Sht As Object
'Set filename of workbook.
'Change as necessary
FName = "Funmathics.xlsm"
'Set location of workbook
'Change as necessary
FFold = "C:\Users\gpeacock\Desktop"
'Get path of workbook
FPath = FFold & Application.PathSeparator & FName
'Unhide all sheets in this workbook
For Each Sht In ThisWorkbook.Sheets
Sht.Visible = True
Next Sht
'Check if file exists
Exists = (Dir(FPath) <> vbNullString)
'If file exists then hide
'"Instructions" sheet...
If Exists Then
ThisWorkbook.Sheets("Instructions").Visible = False
Exit Sub
End If
'If file does not exist then hide
'all sheets except "Instructions"...
For Each Sht In ThisWorkbook.Sheets
If Sht.Name <> "Instructions" Then
Sht.Visible = False
End If
Next Sht
End Sub