I have exactly the same problem - the device is recognised but won't enable, all the status info says it's fine, but the network diagnostics say there may be a problem, and it generally hangs on boot-up and shut-down until I unplug the device. I did get it to boot while plugged in, but it killed my mouse! I quickly learned that Windows 7 is pretty good as a keyboard-only system... As soon as I unplugged the adapter, the mouse came back to life.
All this was using the latest drivers on the Belkin site. Seems to me that an explicit Windows 7 driver is needed.