Environment.TickCount is not enough

Question

I want to know on when was the last time the system was started.

Environment.TickCount will work but it is breaking after 48-49 days because of the limitation of int

Answer 1

public void BootTime(){    
    SelectQuery query = new SelectQuery("SELECT LastBootUpTime FROM Win32_OperatingSystem WHERE Primary='true'");
    ManagementObjectSearcher searcher = new ManagementObjectSearcher(query);

    foreach (ManagementObject mo in searcher.Get())
    {
        DateTime dtBootTime = ManagementDateTimeConverter.ToDateTime(mo.Properties["LastBootUpTime"].Value.ToString());
        Console.WriteLine(dtBootTime.ToString());
    }
}