this whole thing is a nightmare, at least in windows. I had my phone connected and everything was ok. I have a Samsung Galaxy, I\'ve installed the USB driver and it was okay
Have you also tried to change the USB socket in which you plugged the USB cable?
Sometimes one thinks about unplugging/replugging, but not about changing the USB socket in which to plug the cable. All the more since it is correctly recognized by Windows.
I had the same symptoms (Windows recognizing my Samsung Galaxy, but not ADB), and changing the place where I plugged the USB cable did worked for me.