Imports Microsoft.Win32
Public Class Form1
    Public Function DateGood(ByVal NumMonth As Integer) As Boolean
        Dim regKeyPath As String = "Software\Dategod\Erststart"
 
        Dim RegKey As RegistryKey = Registry.CurrentUser.OpenSubKey(regKeyPath, _
          True)
        Dim Start As Date
 
        Start = Format(Now, "M/d/yyyy")
 
        If RegKey Is Nothing Then   ' Schlüssel nicht vorhanden
            RegKey = Registry.CurrentUser.CreateSubKey(regKeyPath)
            RegKey.SetValue("Erststart", Start)
        End If
 
        If (Not RegKey Is Nothing) Then   ' Schlüssel vorhanden
            RegKey.GetValue("Erststart")
            If Now.Date > DateAdd("M", -1, "Erststart") Then
                MsgBox("Erststart")
            End If
            RegKey.Close()
 
        End If
        Return DateGood
 
    End Function
 
  Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
    System.EventArgs) Handles MyBase.Load
        DateGood(12)
    End Sub
End Class