ADB not recognising Nexus 4 under Windows 7

I had a similar sounding situation with my Nexus 4. For me it was an issue with the drivers Windows was installing automatically. I followed the instructions in [Q]Computer won't recognize phone? - Post #8. I had some slight differences on Windows 7.

For me I,

1. Uninstalled the driver from Device Manager
2. Let it automatically install the generic 'MTP device driver'
3. Right clicked on the new device and selected 'Update Driver'
4. Selected 'Have Disk' and pointed it to [android-sdk-dir]\extras\google
5. Watched an 'ADB' driver install.
6. Opened Eclipse to successfully run on my Nexus 4.

Good luck!

Just to confirm a previous comment. I needed to switch my connection to Camera (PTP) mode in addition to enabling Developer options and then selecting USB Debugging from the newly appeared Developer Options.