Post: Criando Windows Services com C# de forma fácil http://blog.albertomonteiro.net.br/2016/04/12/criando-windows-services-com-c-de-forma-facil

GeradorDeRelatorio.cs

public sealed class GeradorDeRelatorio : ServiceControl
{
    private readonly CancellationTokenSource _cancellationTokenSource;

    public GeradorDeRelatorio()
    {
        _cancellationTokenSource = new CancellationTokenSource();
    }

    public bool Start(HostControl hostControl)
    {
        Task.Run(() =>
        {
            while (true)
            {
                //Gera relatorio
                Thread.Sleep(TimeSpan.FromSeconds(5));
            }
        }, _cancellationTokenSource.Token);
        return true;
    }

    public bool Stop(HostControl hostControl)
    {
        _cancellationTokenSource.Cancel();
        _cancellationTokenSource.Dispose();
        return true;
    }
}

NugetInstal.ps1

Install-Package Topshelf

Program.cs

public class Program
{
    public static void Main(string[] args)
    {
        HostFactory.Run(configurator =>
        {
            configurator.Service<GeradorDeRelatorio>(s =>
            {
                s.ConstructUsing(name => new GeradorDeRelatorio());
                s.WhenStarted((service, control) => service.Start(control));
                s.WhenStopped((service, control) => service.Stop(control));
            });
            configurator.RunAsLocalSystem();

            configurator.SetDescription("Sample Topshelf Host");
            configurator.SetDisplayName("Stuff");
            configurator.SetServiceName("Stuff");
        });
    }
}

ProgramFinal.cs

public class Program
{
    public static void Main(string[] args)
    {
        HostFactory.Run(configurator =>
        {
            configurator.UseNinject(new MeuNinjectModule(), new MeuNinjectModule2());
            configurator.Service<GeradorDeRelatorio>(s =>
            {
                s.ConstructUsingNinject();
                s.WhenStarted((service, control) => service.Start(control));
                s.WhenStopped((service, control) => service.Stop(control));
            });
            configurator.RunAsLocalSystem();

            configurator.SetDescription("Sample Topshelf Host");
            configurator.SetDisplayName("Stuff");
            configurator.SetServiceName("Stuff");
        });
    }
}