Eu estou procurando uma maneira de detectar se o usuário esteve ocioso por 5 min, em seguida, fazer alguma coisa, e se e quando ele voltar a coisa vai parar, por exemplo, um temporizador.

Isso é o que eu tentei (mas isso só vai detectar se form1 foi inativo / não clicado ou qualquer coisa):

Public Class Form1

Private Sub form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    'You should have already set the interval in the designer... 
    Timer1.Start()
End Sub

Private Sub form1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles Me.KeyPress
    Timer1.Stop()
    Timer1.Start()
End Sub


Private Sub form1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove
    Timer1.Stop()
    Timer1.Start()
End Sub

Private Sub form1_MouseClick(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseClick
    Timer1.Stop()
    Timer1.Start()
End Sub

Private Sub Timer_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Timer1.Tick
    MsgBox("Been idle for to long") 'I just have the program exiting, though you could have it do whatever you want.
End Sub

End Class