как поменять букву PGP диска ?

Переключить в свойствах.

Очень помогли!:)

Вот как надо:

Click the PGP Desktop Lock icon in the system tray and then click Clear Caches:
Click the PGP Desktop Lock icon in the system tray and then click Open PGP Desktop:
When PGP Desktop opens, expand the PGP Disk control box and select your PGP Disk file:
Click the Mount button (in the top right corner of the window):
When the "Enter Passphrase" prompt appears, click the Options button instead of entering your passphrase:
Select the desired drive letter from the list, then click OK:
Now enter your passphrase and click OK.

На год бы посмотрели.