+1 You could also try using the Activation troubleshooter's "I changed hardware on this device recently" option, it sometimes helps after major updates.
Yeah, same here. A quick tip: make sure you're signed into the Microsoft account linked to your license before you call, it speeds things up. Hope that helps.
+1 Agreed, the troubleshooter after a reboot is the way to go. A small tip: sometimes you just need to wait a day or two for the activation servers to catch up. Hope that helps.
Can confirm. Yeah, that's solid advice. Also, double-check that your Microsoft account is linked in the activation settings, that can sometimes speed things up.