I have a MacBook Air from late 2012 that is running Mountain Lion. I also have PGP Whole Disk Encryption 10.2.1 installed and use it. On Monday night, I suddenly encountered a bad sector and the system completely froze. I hit the power button to restart and now the PGP WDE password screen comes up. After entering my password, I get the Apple logo and a progress bar. Almost immediately after the spinning gear appears under the Apple logo, the system just powers down.
I have used the restore partition to install OS X onto a USB drive (also, this runs really slowly, advice on speeding this up would also be accepted). I have installed a trial version of the latest PGP (now called Symantec Encryption Desktop), and have started the decryption process. It's slow, but it goes. However, after a while OS X tried to mount the drive and gave an error, and now even in Disk Utility, the physical drive does not appear. But if I remove the USB drive, I can still get PGP password screen and get to the Apple logo before it just powers down.
I would like to ask for any advice on how to proceed and recover as much data as possible.