The useful advice
l3wish, I had the same problem: I did tried all I could, but ADB did not detected my device. I many times restarted adb-server, rechecking USB-debugging and tried some drivers (and Google drivers too) — nothing useful. Your advice to download the newly version of ADB has solved this trouble and the fresh ADB is detecting the device, but my Firefox (v. 43) cannot connect to Internet and your next advice for the FoxyProxy plugin has solved this trouble too. Now all has worked fine.
I live in the russian country and have only 3G Internet, so you much helped me. I very appreciate it, thank you very much! Very, very much!