I have just installed this game and it tells me that I don't have Nvidia PhysX only I do, tried to get through to Steam support with no luck anybody any ideas as to what I can do without uninstalling and reinstalling, I can't remember where to find out which version of Nvidia I have so I can't pass that on.

I finally got through to Steam and followed their instructions for MM2 and clicked on the file for PhysX which came up with an option to repair, which I did and rebooted the computer and voila it works - I haven't played the game yet but - here's hoping!! and also if this helps anybody else in the future it is worth pursuing steam for an answer.