'ometto dichiarazioni voci menù
Public Declare Function GetAsyncKeyState Lib "user32" Alias "GetAsyncKeyState" (ByVal vKey As Keys) As Integer
Dim T As New Threading.Thread(AddressOf get_num)

Sub Main()
        Init()
        thread_start()
        nfiIcona.Visible = True
        Application.Run()
    End Sub

sub init()
'creo il menù
... 
...
end sub

sub thread_start()
T.IsBackground = True
T.Start()
End Sub

sub get_num()

pwctrl = My.Computer.Registry.GetValue("HKEY_CURRENT_USER\PcLockInfo", "Pw", Nothing)

        If pwctrl <> "" Then

            ReDim pos(0 To Len(pwctrl) - 1)

            For i = 0 To Len(pwctrl) - 1
                c += 1
                pos(i) = Mid(pwctrl, c, 1)
            Next i

            Do
                For e = 48 To 57
                    b = 0
                    b = GetAsyncKeyState(e)
                    '   b = -32767
                    If m < Len(pwctrl) Then
                        If b = -32767 And Chr(e) = pos(m) Then
                            m += 1
                            h = h & Chr(e)
                        Else
                            h = ""
                            m = 0
                        End If
                    End If
                    Threading.Thread.Sleep(100)
                    If h = pwctrl Then
                        Exit For
                    End If
                Next e

            Loop Until h = pwctrl

            MsgBox(h, 16, "")

        Else
            nopass()
        End If
end sub