A 4 year old laptop? It has been sold several times, dropped, virus infected, stolen again, had the hard drive replaced, dropped again, and had keys broken off.
The current possessor of it (if it hasn't simply been tossed in the trash by now) has no clue that it may be stolen.
And just having the serial number will not help. Maybe call Sony to see if it has been sent in for service. Do you have a police report that includes the serial number? Do you have the original receipt? Just having the box doesn't mean a whole lot.
It's gone, man...let it go.