It sounds like there was actually an underlying Windows issue caused by the power failure that somehow managed to right itself after a reboot. Ok, make that 6 or 7 reboots.
Since it was actually getting through the Bootguard to the Windows login, either the Windows installation would not accept the password, even though PGP did, or the handoff process between PGP and Windows was experiencing issues.
I'm glad the issue corrected itself, and you were able to access the system. That is not always the case after a power outage! That is why we recommend always checking the "Power Failure Safety" box when encrypting!