What you can do is create a binary value in the registry, in the path
HKEY_LOCAL_MACHINE\SOFTWARE\AGEIA Technologies\
So run regedit, and on the left, go to that "folder". Then on the right, right click in the white space, choose NEW and then choose Binary value.
Rename it: enableLocalPhysXCore (mind the caps!)
Then double click that value and fill in your mac address in the data field.
You can look up your mac address by opening command prompt and typing
ipconfig /all
One of the lines will say
Physical Address. . . . . . . . . :
The 12 characters after that are your mac address.
So in the end, the content of enableLocalPhysXCore should look like this:
Just start typing the 12 chars and it will end up like that. Never mind the four zeroes on the left