Use Inno Setup to uninstall another application not installed with Inno Setup during installation

Question

I have an old VB6 application that deploys using the very old 16-bit version of InstallShield. I created a new installer with Inno Setup so that it is 64-bit for my update VB6 application.

All my users already have an existing version of InstallShield. I am currently running Inno Setup. The problem is that I do not want to overwrite the old InstallShield installation files, so my Inno Setup is installed in a different directory. This causes problems because now I have two versions installed with two separate icons.

I need a way to invoke the uninstaller of the old InstallShield application when I install the new version of Inno Setup. How can I remove the Windows uninstaller from the Windows installer and uninstaller through Inno Setup? If I reuse the application identifier for the InstallShield version, which will be the same as Inno Setup, and then manually delete the old files, will this work?

Answer 1

InstallShield, HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\, UninstallString. : Inno Setup, _is1 AppId . , Windows - .

PrepareToInstall.