Apart from a simple financial calculation (which you probably did, and still left you wondering), this is usually a subjective decision.
Personally, I'd go with just buying a new machine. Servising parts is expensive, and on top of that, when electronic components start to go haywire, chances are something happened that caused that. And there is a possibility that other components are just waiting for their "best moment" as well (you know, ... the kind which will cause you the most grief).
Apart from the warranty repairs, servising laptops in terms of price is a murder. I recently gave my left leg and three of my kidneys just to get the service man to change my fan.
Go with a new clean buy ... imho.