When installing PGP Desktop on a system with Sophos, after entering your login information, Windows does not load the operating system.
This issue is caused by a conflict between a Sophos dll and a PGP Desktop dll. This is due to the order which the operating system loads the Sophos and PGP Desktop application dll files thereby causing PGP Desktop to affect the Data Execution Prevention (DEP) feature in Windows to fail.
This issue only occurs on systems which the Data Execution Prevention (DEP) feature in Windows is enabled. The Data Execution Prevention (DEP) feature is enabled by default in Windows XP Service Pack 2.
For more information regarding the Data Execution Prevention (DEP) feature in Windows, click the following link for a Microsoft Help and Support article. Data Execution Prevention (DEP)
This issue can be corrected by the uninstalling and re-installing the PGP Desktop and Sophos software programs. The installation order of the software is key to resolving the above described issue.
After uninstalling PGP Desktop and Sophos Anti-Virus, install the software in the following order: