You have Ageia PhysX PPU card?
I hope this helps you to get back on business. I made originally this for myself as i did reinstall my windows couple times..

You need this:
PhysX 0.2a.7z md5sum: 75C75170AE844F92C3AB730286CF3317

If you running on todays nVidia GPUs older PhysX titles then there is PhysX Legacy driver package:
NVIDIA PhysX Legacy System Software 9.12.1031

After extracting *.7z-archive. Install things in order so first ageia_physx_7.11.13_systemsoftware → then as next PhysX_8.09.04_SystemSoftware and... → finally install PhysX_9.10.0513_SystemSoftware as a last and newest Ageia's drivers.

Copy&paste folders Program Files (x86) and Windows at C: -drive root and overwrite files if some exists. → Run PhysX Demos.reg to add windows registery missing registry values → Double click TrayIcon 64bit - shortcut to go folder where should be by now TrayIcon.exe and run it →

Attention!%programdata%\Microsoft\Windows\Start Menu\Programs\Startup (copy&paste to windows folder address bar) here you can copy a shortcut from TrayIcon.exe to auto run and have that Tray program running at every windows boot so its makes things easier for you. It's not needed. It's up to you.

... or not but click on to choose Ageia PhysX and then click OK to be finished. Go to Demo tab and have fun :) Remember first of course install carwash demo from my archive!