Perchè non ti piace la funzione Dir?
codice:
Dim rootdir As String
Dim subdir As String

rootdir = "C:\"
subdir = "Programmi"
'subdir = "Programmo"

If Dir$(rootdir & subdir, vbDirectory) = "" Then
   MsgBox "Cartella non trovata!"
Else
   MsgBox "Cartella trovata!"
End If