N2D, like everyone said, bow maintenence is not really difficult at all. The important thing to always remember is to fully research what you're doing first, then, take your time doing it. I too ran into the same situation years ago, being tired of depending on shops to do work and then find out they don't do a very good job to begin with. I have only one shop that is close that I would ever let work on my bow. Unfortunately, they're not a Bowtech dealer so any warrenty work would have to go to the clowns I bought it from. So, I do everything myself except warrenty work.

As for your string, I'd just replace it and the cables. I'm not sure how old they are, but it never hurts to replace them if they're over a year old. Winners Choice is a fine product, albeit over priced, but very good.