Function Controllo(ByVal nome As String)
        Dim let1 As OleDbDataReader
        Dim cmd1 As New OleDbCommand("select * from tbllog where [user]='" & nome & "'", con)
        try
        con.Open()
        let1 = cmd1.ExecuteReader
        let1.Read()
        If let1("user") Is DBNull.Value Then
            ver = "nullo"
        Else
            ver = "pieno"
        End If
        let1.Close()
        Catch ex As Exception
        MsgBox(ex.ToString, MsgBoxStyle.Exclamation, "errore")
        Finally
        con.Close()
        End Try
    End Function