Concerning the reformatting, it should be possible to use the typical "boot and nuke" approach. It would be recommended to decrypt first, however, as occaisionally the partition information is not completely removed during the reformat process, and the drive may still show as encrypted after the OS and PGP are reinstalled.
Regarding the question about recovery options, you should create a Recovery Disk for your version of PGP Desktop or Symantec Encryption Desktop. You need to use the correct iso for your version. The iso files can be found here:
http://www.symantec.com/docs/TECH210725
Some other basic troubleshooting and Recovery steps can be found here:
http://www.symantec.com/docs/TECH149679
Note that while you can decrypt using the recovery CD, it is faster to slave the drive to another machine with PGP Desktop installed.