My Windows 7 box has not been recognizing my awesome USB Das Keyboard when I dock my workstation in the morning. The solution was to update the power settings so Windows would not ignore USB devices after powering down.
Steps to Fix:
1. From the Start Button, select "Control Panel" and then "Power Options"
2. Select "Change plan settings" from your favorite power plan.
3. Select "Change advanced power settings"
4. And finally set the "USB selective suspend setting" to "Enabled".
5. This should force Windows to keep the USB ports active and recognize your devices. It may take a minute when you dock your laptop for it to recognize the keyboard. Please be patient. This is windows.