@gadget42: I've used that can once on an old dial-style am/fm radio; it could just be the scenario at hand, but it seemed to have left a white powdery residue when it dried; thus we've avoided it since. Any similar results on your end?
@Rich: The sad truth to electronics (physics with metals in general, too) is when two different metals make contact over a period of time, the composition
tends to lead to a chemical reaction between the metals. For example, back in the day when all homes and businesses were piped with copper water lines... many people used (much cheaper) steel and aluminum/tin straps to bolt the plumbing to the structure - which on the date of the installation looks just as professional, but because of the different metals being pressed against one another for long periods of time, it causes a special type of break-down.
See:
https://www.google.com/search?q=galvanic+corrosion Now the funny part with electronics (such as USB ports, PCI, etc.) is people talk about how gold pads on cards make for better conductivity - which is
true... however, if the partnering side is not also gold (most are copper) you run into the same situation.
In the Op's case, there's a very good chance the WiFi PCB is "coated" (oxidized) and if it's true, the female pins within the laptop are also subject to the same residue. When you make a clean connection (new USB hub, especially if self powered) you're taking pins 1 and 4 out of the equation. Remove the power from the hub and you're
likely to start seeing problems. (A USB Port voltage meter would be a good way to prove the situation as to whether or not there's ample juice to power the WiFi device; wiggle the meter in the USB socket and it may even black out if connectivity is that bad.) From a technician's perspective, both the device
and the laptop are burnished/cleaned, tested for proper feed voltage and ground and then burn-tested to ensure the problem no longer exists. (Granted, in today's day, most techs working on an old XP laptop would instead respond with "...it's old. Get a real machine!" Sad to imagine what they think about older
people instead of tech.