Automated PC shutdown program memory

[JohnPhilipps]

good morning,

I made a little VB app to shutdown a laptop after it has been powered on for 2 1/2 hours, and giving the user a little over 8min warning that it is about to be shutdown.
However I have nothing in place to stop the user from restarting the device once it is shutdown.
What I would like to integrate in this, is a sort of memory where if the user doesn't wait at least 30 minutes, the shutdwon will re-iniate immediatly.

May I request guidance? I included the code I did so far.

Thank you
John

Public Class Form1
    Private Declare Sub Sleep Lib "kernel32" (ByVal dwmilliseconds As Long)

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        'hides the form
        Me.Visible = False

        Sleep(9000000) '2 and 1/2 hours
        Shell("cmd /c shutdown -s -t 500 -f") '8:15min
        Close()
    End Sub
End Class

[debasisdas]

May be you can store system shutdown time into registry or any other location and read the same on system start up. If the difference is < 30 mins call the shutdown routine again.

[JohnPhilipps]

OK, so read the time value of the PC, store it, and have it read by the app upon startup.
Thanks for the tip,

I will try that approach