Because InstallShield 3 is legacy software, it is no longer sold by Revenera (formerly Flexera). However, legitimate copies can be found:
Warning: Avoid random download sites offering "InstallShield 3 standalone." Many are infected with malware. Always verify SHA-1 hashes against known good copies. installshield 3 32bit generic installer best
Double-click the new SETUP.EXE. The generic engine will read your original SETUP.INX and DATA.TAG and proceed with the installation. Because InstallShield 3 is legacy software, it is
Troubleshooting Tip: If you get an error about "Unable to load
_ISRES.DLL", manually copy_ISRES32.DLLfrom the engine pack intoC:\Windows\SysWOW64. Double-click the new SETUP
Do not download from forums with low reputation. Stick to known preservation libraries.