None of these worked for me.
Do a full computer search and search for the file. If you cannot find it, check your graphics card model and make and google the "PhysX Driver for....." insert your card model and make.
Dll's should be either in the game directory, the system32 folder (usually C:\Windows\System32) or in the install directory of your graphics driver.
Here is a general discussion on what it is and how to generally fix it. I would recommend to download the PhysX Drivers from your Graphics Card manufacturer first, though, as that usually fixes it. :
https://www.nvidia.com/en-us/drivers/physx/physx-9-19-0218-driver/
CM Edit: For driver updates it's usually best to acquire them directly from your relevant hardware manufacturer's site.
Hope this helps
