I have this problem, but only inside a remote desktop window.
My keyboard works fine locally on my computer, but it acts as if the windows key is forced down when I am in a remote window to a specific computer. I think I pressed the window key and something else just before it started happening. I tried logging off the remote computer and logging back in and it did not solve the problem.
Is there a windows application or service that starts to hold the windows key down for you? What is the shortcut to turn it back off?