I have a Nexus 4 with Android 4.3 and I am trying to connect the device to a computer with Windows 7 64bit.
I installed the latest drivers and the latest adb>
adb>
1.) Delete ~/.android/adbkey on your desktop machine
2.) Run command "adb kill-server"
3.) Run command "adb start-server"
You should now be prompted to accept debug key.