Detecting if a custom program is already installed and taking its settings

[jessican]

Hi there!

I'd like to know how to make the installer detect if a custom program is already installed on a computer
and if it is installed, to take settings (PATH values/environment variables, etc.)

Basically - I'd like to program to take over the same path values, environment variables as another program its replacing.
(A very old version of the same program, installed using installShield)

Also - Can my package make this other old program to uninstall ?

Thanks!!

[FrancescoT]

Dear Jessican,

I have already replied to you about this matter when you asked a similar question.

You can query the target registry to check for an installed package.

This information is stored under:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\<PRODUCTCODE>
or (if it's a native 32 bit package installed on a x64 system)
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\<PRODUCTCODE>

*where <PRODUCTCODE> is the GUID assigned to the specific third party product. This is generally the same and identical with different version of the same product.

To find the <PRODUCTCODE> you need to manually search through the registry of a system where the package is already installed, or in case you developed the package, use the its productID.

To uninstall the package, you can query the value of "UnInstallString" key from the same registry path.
Then you can use the "UnInstallString" with "Run Program" or eventually with "(un)Install MSI package" (if a MSI package).

The above registry path also stores the path where the package has been installed ...if I recall, it should be the "InstallDir" key.

For what concerns environment variables, unless the setup package stores such information somewhere (by default it doesn't), the only option is to query the target system for that variables.

Hope this helps you.

Regards

[jessican]

thank you!, by query do you mean the read registry function ?

[FrancescoT]

Yes, I mean to read for that specific registry Keys of course.