I've already sent a message about this to support, and I'm sure that the PI team will respond as soon as they can. But....
I decided to upgrade my PC to Windows 10 and did a clean install. In doing so I of course needed to reinstall PI. The registration info provided by PI is only good for one installation, and after the old installation there was a small license file in the program folder. This "pixinsight-license" file is needed to activate and use PI, but unfortunately I didn't know that and the file got deleted during the win10 install.
I'm just placing this message here in the hopes of getting a faster response from the PI team or anyone. I'd really like to start processing images again...