well when I started up my computer, I got a message from the Action Center saying to reactivate Windows 8, when it was activated and fine yesterday.
I used W!nvator the first time, and then I used my WMC key. This morning, I used Microsoft Toolkit to reactivate it. Version I have is: Windows 8 Pro.
My point of view : too much different processes for activation, you should try a fresh reinstall using MTK only.
My Windows 8 Pro (legal - Retail) with MCE (the free key - Retail - legal) got deactivated Sunday. Had to run the "Slmgr.vbs /ato" to reactivate. I have Office 2013 with KMS on the laptop though.
It's maybe because of the Internet connection. I had several times to reactivate to while on the move using my Laptop which has only legal apps installed. Also a simple restart would activate again. As I use a lot Macros, I created one for re-activation and I need only to press my Hot-Key (3 key's at the same time), That works fast and well.