A hard disk already encrypted with PGP Whole Disk Encryption (PGP WDE) and then the system crashes before the hard disk is fully decrypted. When attempting to rebuild the system, you try to format the disk, but you cannot access the disk.
The possible cause is that the Master Boot Record (MBR) is corrupted.
You can use a Linux live CD to boot the machine, and then use the following command to wipe the MBR.
dd if=/dev/zero of=/dev/hda bs=446 count=1
The drive ID (sda, sdb...) can be seen with this command: