I have the ff macro which works great and saves the spreadsheet, but I need
an additional verfication before the macro is run:

Sub Save_As()
Dim objShell As Object
Dim objFolder As Object
Set objShell = CreateObject("Shell.Application")
Set objFolder = objShell.Namespace(&H5&)
Application.Dialogs(xlDialogSaveAs).Show _
objFolder.Self.Path & "\" & Range("f1").Value & ".xls"
End Sub

I need for the macro to verify either the group of cells A1, B1, C1 OR the
group of cells A1, B1, D1 be populated before the above macro is allowed to
run.
If neither of the two criteria are TRUE, then an error message window comes
up to say "Populate Required Fields" then give the user an option to Cancel
or Retry the operation.

Thanks much.