Problem: Asus Nexus 7 not recognized by adb when correctly installed and connected
Setup: Asus Nexus 7 tablet Windows 7 64 bit OS
Steps taken:
In my case when I got an empty list using "adb devices" I found that the device manager showed the Nexus 7 tablet under 'other devices' with that dreaded yellow exclamation point indicating that the driver was not installed correctly. Why Windows recognized part of the tablet file system, I don't know. In any case I manually updated the driver to the google usb driver in android-sdks\extras\google.
Then adb gave me the following:
C:\Users\Brian\android-sdks\platform-tools>adb devices
List of devices attached
015d25785b601611 device
instead of a blank. I hope this doesn't mess anything else up but I can now talk to the device.