Check if a user is an admin and if not try to elevate the application by restarting itself. When using the verb "runas" User Account Control will popup a dialog and ask for permission to include administrative rights or to login as an administrator.

Setup.cs

public static string ProcessFilename
{
    get { return Process.GetCurrentProcess().MainModule.FileName; }
}

private static bool HasAdministrativeRight()
{
    WindowsIdentity windowsIdentity = WindowsIdentity.GetCurrent();
    return windowsIdentity != null
            && new WindowsPrincipal(windowsIdentity).IsInRole(WindowsBuiltInRole.Administrator);
}

private static void RestartElevated(string command)
{
    var processInfo = new ProcessStartInfo
    {
        Verb = "runas",
        FileName = ProcessFilename,
        Arguments = command
    };
    try
    {
        Process.Start(processInfo);
    }
    catch (Win32Exception)
    {
        //Do nothing. Probably the user canceled the UAC window
    }
}

Part of my blog post How to open a link in another browser.