I've had this computer for many years and it has been trouble free. Recently, however, it's been losing the wifi signal. It'll keep it for a while, but then I'll see it fluctuate and eventually die. I can't seem to bring it back to life. I have an iPhone, Apple TV and a laptop that all seem to have no trouble pickng up the wifi signal. Would this be a software or hardware issue? Could my airport card be dying? If so, is it fixable? Any help would be appreciated.