Public Class Form1
    Implements IMessageFilter
 
    Private Const PRINTKEY As Integer = &H2C
 
 
    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Application.AddMessageFilter(Me)
    End Sub
 
    Public Function PreFilterMessage(ByRef m As System.Windows.Forms.Message) _
      As Boolean Implements System.Windows.Forms.IMessageFilter.PreFilterMessage
        If CInt(m.WParam) = PRINTKEY Then
            Debug.WriteLine("Bla!")
        End If
        Return False
    End Function
End Class

Those people who think they know everything are a great annoyance to those of us who do - Isaac Asimov