You must have the password to the drive otherwise you wouldnt be able to start it up. You can use the password to add another user to be able to decrypt.
Or you can use the recovery CD to decrypt. That will take a very very long time (Days and days)
Please mark posts as solutions if they solve your problem!
Is it managed or unmanaged client?
If managed then u can used Recovery token.
Found this one as well :
1. User's Passphrase to login
2. If multiple users were added, any other user may try using their passphrase to login.
3. WDRT token
4. WDE Admin Passphrase (If configured), (In case of PGP Standalone Desktops, this option doesn't work).
5. In case of Standalone machine, we may use another user's passphrase if it was already added in 'WDE user access' while the machine was in working mode.
6. Use of Security questions and answers is one of the options, if it was configured.
7. Recovery CD.
8. we can slave the drive to another working machine which has PGP installed on it and try decrypting using the PGP console or PGPWDE commands.
9. If above steps doesn't work, the only option is to Format the hard drive and Re-install PGP. (We may check for corrupt hard drive sectors, if any, Because PGP encryption would always fail on bad hard disk sectors. Run Chkdsk and Defragmentation on the hard disc for the same).
10. You may try 3rd Party Vendor to retrieve the data from the Encrypted Hard disk, Like Active Recover File Partition.
Without key data cannot be decrypted.