I unlocked new windows features by applying a Windows 8.1 Pro key from my MSDN subscription. Now the surface shuts down every night and complains in the event log that 'hardware changes were detected'
Well...I do not have an MSDN subscription but I believe the key should be used on more than one device??
I am not saying this is exactly the issue but it kinda sounds like a key problem because if you take a key that has been activated on one device and switch it to a different device, it detects the changes in hardware and the key becomes invalid. Sounds like it has something to do with this in some form.