"I suppose I can try my old video card and see if it is different."
That's exactly what I would do...
If it works with your older graphics card, you will have to wait for Microsoft to update the WEI. Your Physx graphics card may just be "too new".
TIP: Make sure that you've done all Windows Updates, first. In theory, WU should find and install all the latest Physx Device Drivers. We mere mortals shouldn't have to do this ourselves anymore.
My newly installed Win 7 Home Premium reports my Windows Experience Index fails to compute. Darn and I wanted to see if I got above 7 on the rating. I used to have 5.9 with Vista, and now it won't do it at all. This does not appear to be a big problem in doing anything but looking at the numbers but I wanted to know if mine was bigger than yours. oops my freudian slipped. Of course driver is latest, tried 3 in fact and turned off the Physx and 3D. Still no help. Nvidia 250 OC, 8 gigs RAM, Win 7, 64 bit. I suppose I can try my old video card and see if it is different. I have an 8600 in the bottom drawer.

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