A USB keyboard in a Microserver is causing the machine to become very unresponsive
Solution 1:
I am going with a Key is stuck on the keyboard. And that is my final answer. Try working all the keys on it up and down hard, to free up anything that might be stuck, including the "qualifyer" keys. or use a different keyboard.
Solution 2:
The only time I've seen this is when the USB device is faulty, as per psycogeek's stuck key. If you're certain this is not the case then I would then suggest that the port (or controller) on the device itself could be faulty. Have you tested the keyboard with the other servers?