F5 doesn't generate a KeyPressed event, use the KeyDown event instead:
Private Sub Form1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
If e.KeyCode = Keys.F5 Then
MsgBox("F5 pressed", MsgBoxStyle.OkOnly, "nobugz was here")
End If
End Sub