Can i register for quickheal laptop tracer service even if i have'nt lost my laptop?

You would have to use it BEFORE it is ever stolen. After it's stolen, it would be TOO LATE to install anything identifiable as you wouldn't have the laptop to install anything on it because you wouldn't know where it is. So you use these types of programs before so they'll install the identifing markers which will allow them to trace where your laptop is. :)