Puoi usare una cosa tipo:
codice:
filedacercare = "nomedelfile"
cartellabase = "C:\"


Dim fs As New FileSystemObject
Dim f1 As Folder
Dim f2 As Folder
Dim f As File


Set f1 = fs.GetFolder(cartellabase)


For Each f2 In f1.SubFolders
    For Each fi In f2.Files
        If InStr(fi.Name, filedacercare) Then
                    'vedicosafare
        End if

        Next
Next


edit: aggiungi la reference a: "Windows Script Host Object Model"