I know our hardware engineer, John, is looking into this. I also emailed Dave D. and he mentioned this is Windows 7 running on a PC and not on an Intel Mac. That's very useful because I don't think we've ever seen the keyboards not work on a PC. I can't imagine how the 64-bit version-ing of 7 could make a difference. I run it on my machine here but it's run on an Intel Mac. Can you attach dxdiag.txt from one of these machines? Also, can you make sure you are logged in as an administrator when you try plugging it in? Perhaps also try unplugging any other USB devices that happen to be connected before you do so. Finally, are you connecting directly to one of the computer's USB ports or are you going through a hub or extension cable of any kind? Just some ideas to get started with. Hopefully John will have something more solid for you shortly. If not, you can mail one of the boards to use here in NYC (at our expense of course) and we can do some tests on them to see what's up.