Without even looking, I can tell you it's not worth $6000. Three years is a couple generations in computer terms, making whatever laptop you have out of date, considerably, and worth considerably less than what you paid for it.
That's the sad reality of computers. They depreciate in value very quickly. That doesn't mean their usefulness decreases, though. I'm sure a $6000 laptop purchased as far back as five years ago is still capable, just not worth anywhere close to $6000.