Warning to anyone migrating to a new PC, reinstalling OS, or just anything that requires you to reinstall GMPC and you are without a bundled GPS that acts as a hardware license key.
Garmin has turned off the activation server for the software.
That means if you don't have a bundled hardware GPS receiver, you cannot activate the software at all, not even use trial mode.
Garmin will not tell you how to preserve your old activation at all. You now have a piece of software that you paid money in good faith, that you cannot continue to use. Adobe deactivated their CS2 activation server and gave out serials (inadvertently to everyone) so that anyone wishing to use the 'obsolete' software can continue to do so.
I'm simply upgrading to a bigger SSD and now I'm stuck. I have yet to format my old drive because I KNOW somewhere in there lies my GMPC activation!!