Check if your systems satisfies this requirements:
From 10.2 release notes:
PGP Desktop can be installed on systems running the following versions of Microsoft Windows operating systems:
Windows XP Professional 32-bit (Service Pack 2 or 3), Windows XP Professional 64-bit (Service Pack 2),
Windows XP Home Edition (Service Pack 2 or 3), Microsoft Windows XP Tablet PC Edition 2005 SP2, Windows
Vista (all 32- and 64-bit editions, including Service Pack 2), Windows 7 (all 32- and 64-bit editions, including
Service Pack 1), Windows Server 2003 (Service Pack 1 and 2).
The above operating systems are supported only when all of the latest hot fixes and security patches from Microsoft
have been applied.
Note: PGP Whole Disk Encryption (PGP WDE) is not compatible with other third-party software that could
bypass the PGP WDE protection on the Master Boot Record (MBR) and write to or modify the MBR. This
includes such off-line defragmentation tools that bypass the PGP WDE file system protection in the OS or
system restore tools that replace the MBR.
Any security software installed? DeepFreeze? Raid mirroring?
Dual Boot system?
Send screenshots and error messages .