how to debug a windows services without installing it

I suppose you've written the service on your own?

One debug possibility:

1) Add a method to your service class like:

public partial class YourService : ServiceBase
{
    public void DebugStart()
    {
        this.OnStart(null);
    }

}

And the main should look like this, e.g.

static void Main()
{
    if (System.Environment.UserInteractive)
    {
#if DEBUG
        YourService s = new YourService();
        s.DebugStart();
        
        bool run = true;
        
        do
        {
        // dirty!
           Thread.Sleep(1000);
        } while(run);
        
        
        s.Stop();
        s.Dispose();
#endif
    }
    else
    {
        ServiceBase[] ServicesToRun;
        ServicesToRun = new ServiceBase[] 
        { 
            new YourService() 
        };
        ServiceBase.Run(ServicesToRun);

    }
}

Instead of the dirty forever loop you could open a modal window. To stop the service and debug the service shutdown, set a breakpoint in the forever loop and set run = false.