Restoring SQL DataBase by Code from VB 2010

Hi guys:
Can anyone help please
I am working in VB 2010. My program works wit SQL DataBase "dbCARS" . I Open the conections, make my Queries and Close them and Disposed Inmediately.
From my program I Back-Up the DB and works fine but the Restore Sub Throws this error messege:

"Exclusive access could not be obtained because the database is in use" RESTORE DATABASE is terminating abnormally.
I have no idea what is wrong. I am positive all conections are close.

Private Sub RestoreDB()

Dim con As New SqlConnection("Data_ Source=(local);Initial Catalog=dbCARS;Integrated Security=True")

        Try
            Dim strResSQLsentence As String = "RESTORE DATABASE dbCARS FROM DISK='" & txtDBToRestore.Text & "'"

            con.Open()
            Cmd = New SqlCommand(strResSQLsentence, con)
            Cmd.ExecuteNonQuery()
            MsgBox("DataBase have been restored.")
            con.Close()

        Catch ex As Exception
            MsgBox("Could not be restored.", vbOKOnly)
        Finally
            con.Close()
            con.Dispose()
        End Try

    End Sub

Thanks in advance.