we are creating an installer which adds functionality to another product by adding some new dlls into it's installdir folder. As such we need to detect if the parent application is running and tell the user to shutdown the app before proceeding with our installer. We are using a basic msi installer.
There's a sample "List and Shut Down Running Applications" at http://www.installsite.org/pages/en/isp_ext.htm . It's in InstallScript, you might either use a similar script in a custom action, or re-create the same as DLL in C.
