ADB recognizes one phone but not another

I have two identical Moto Droids. Both are up to date (2.2). I have been using one of the phones for development for some time. I now want to install my app to the other phone but cannot get adb to recognize it.

Platform: WinSvr2008R2

• Eclipse with android pluig i开发者_如何学Cns.
• USB debugging: on.
• Have verified both phones have the same options and settings.
• The phone that is not recognized shows up in Windows Devices.

Is there some kind of hidden binding that prevents adb from working with mulitple devices?