I get a “failed to initialize the physics system. Please ensure you have an updated version" error.
Sometimes, you may end up with this message even if you have PhysX system software installed on your system (seems to have only with some NVIDIA cards). The only possible solution we have found so far is to uninstall the existing PhysX version and installing from the setup that came with the Mass Effect 2 DVD disk.
I've done both of what you said. Uninstalled completely (PhysX) -> I get the window about not having physx installed. And if I install the PhysX from the ME2 Disk, it starts the .exe and then it end ups in a black screen not responding to anything.