I have done the obvious -- the USB driver was installed from the latest Android SDK, and USB debugging was turned on in the tablet.
When the Nexus 7 is connecte
I had a similar issue and tried the other suggestions.
Utilizing the PdaNet driver in the download from http://www.junefabrics.com/android/download.php is what finally did the job and allowed me to finally connect via ADB. Prior to installing the driver from here I was unable to recognize my Nexus in order to sideload the new Android 4.2 on my device.
I am running Windows 7 64 bit with my Nexus 7.