I got my keyboard working again following the procedures described above. However, I had to add extra steps:
- In addition to step 2 & 3, I had to uninstall "HID Keyboard Device" drivers. There were two or three of them listed under the Device Manager.
- Ensure that the charger is plugged-in (not sure if this is related but my device was plugged in when I got the keyboard to work again)
My surface pro stopped working around two weeks ago, probably due to an update.