[strike]Might you give us your CPU and GPU model along with your OS and the game in question that you need the legacy drivers for?
You could try uninstalling the legacy drivers and see if that allows you to install the normal ones and fixes the issues in newer titles. If so, then for sure the legacy drivers are the issue. My suggestion is to then clean wipe the PhysX driver and run the installer for the version that’s included in the game installer for the old title. Once that’s installed, launch the game to verify it works. If it does, run the installer for an up to date package (not the legacy marked ones) and see if that will complete and work.[/strike]
edit....
well, if you don't need the legacy ones any more. just uninstall the legacy drivers, restart, and install the current ones. that should resolve your issues.