Installing PGP7 on Windows XP SP1
(this information is provided by Dave English)

Microsoft Windows has long had an Application Compatibility system, to
allow software intended for earlier versions of Windows to be used on
later versions.  When making the software work is beyond the
capabilities of the system, then it can prevent the software being
installed at all.

PGP7 is an example of something that cannot be made to fully work on
Windows XP.  We will all have to wait for PGP8 to do that.  But in the
meantime, many of us find the parts of PGP7 that will work on XP very
useful none the less.

When Windows XP was first released, Application Compatibility only
recognised one very specific version of PGP7 & prevented the
installation of just that one.  Now with Windows SP XP1, installation of
all versions of PGP7 is prevented.

Those who already have PGP7 installed on Windows XP, before they install
SP1, will not find that the new Application Compatibility rules affect
the operation of their PGP at all.  That is because the rules are only
triggered when an application is installed, not when it is run.

Fortunately the rules can be overridden, for those of us that wish to
use PGP7 on Windows XP - warts & all.

There are three ways to install PGP7 on Windows XP SP1.  The first is to
install the Microsoft Application Compatibility Toolkit & use its
administration tool to disable the two relevant rules.  The second is to
make two settings in the registry to disable those rules - just the same
changes that the tool would have made.  The third is to install PGP7 in
a slightly tricky way - so that Application Compatibility never spots
the software being installed in the first place.

The application Windows Application Compatibility Toolkit 2.6 can be
downloaded from Microsoft.

<URL:http://www.microsoft.com/downloads/release.asp?ReleaseID=42071&area=
search&ordinal=1>

Install it and then run the Compatibility Administrator Tool.  In the
left hand panel open the System Database & within that open
Applications.  Scroll down to find PGP Desktop Security 7.x .  Select it
& in the right hand panel you should see two rules, both for Setup.exe .
Right click & disable each of those two rules.  You will then be able to
install PGP7.

Alternatively, for those confident with the registry, just add these two
entries:

REGEDIT4

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows
NT\CurrentVersion\AppCompatFlags]
"{4799c784-ed00-4682-b3f5-13dd676e6827}"=dword:00000001
"{611ba544-f98f-412a-8cd6-d57d591b8c73}"=dword:00000001

That way there is no need to download & install the toolkit.

Finally, to simply side step Application Compatibility, install PGP7 in
this way.  Run the self extracting .exe for your PGP 7.x installer. When
the Microsoft "PGP Desktop Security 7.x" is incompatible with this
version of windows" dialog comes up, do not press cancel but go to look
for your temporary files folder.  Mine for example is:

C:\Document and Settings\username\Local Settings\temp

Note that to find this using Windows Explorer you will have had to set
the option to show hidden files & folders, because the Local Settings
folder is hidden.  In it there should now be a new numbered folder
PGPnnnn & within that a folder called Disk1 .

Copy the Disk1 folder elsewhere.  You can now press Cancel at the
dialog. Now copy the Setup.exe file in the Disk1 folder to say
fred.exe & run that fred.exe .  When installation is complete you can of
course delete your Disk1 folder.

This works because the application compatibility stuff activates when it
sees you run setup.exe in a directory which contains PGP version 7
files. But what you have just done is not run setup.exe, but some other
.exe, so no rule is triggered.

For those interested, the original rule in Windows XP, guid
{611ba544-f98f-412a-8cd6-d57d591b8c73}, prevented just PGP desktop
Security 7.0.3 being installed.  It triggered when Setup.exe was run in
a directory containing a PGPdisk.exe who's resources matched:

        BIN_PRODUCT_VERSION=7.0.3
        COMPANY_NAME="Networks Associates Technology, Inc."
        PRODUCT_NAME="PGP Desktop Security"

With Windows XP SP1 there are now two rules, both for running Setup.exe
.  The first, still guid {611ba544-f98f-412a-8cd6-d57d591b8c73}, now
matches a PGPdisk.exe & the second a new guid
{4799c784-ed00-4682-b3f5-13dd676e6827} for PGPnet.exe .  For either file
the match is made to:

        BIN_PRODUCT_VERSION=7
        COMPANY_NAME="Networks Associates Technology, Inc."
        PRODUCT_NAME="PGP*"

In other words, any version 7 with any name starting "PGP".

Remember, with any PGP7 installation on Windows XP, make sure to avoid
installing PGPnet - either for PGPfire or for PGPvpn .  If you do
install PGPnet then your Internet connectivity will be broken until you
mend it with the "sc config ipsec start= system" command line - it is no
doubt that pitfall which the Application Compatibility rules are trying
to save you from.