In theory, USB 1.1 and 2.0 are fully compatible. But that's the theory, of course...
What I don't understand is this: do your USB ports work at all? If not, perhaps they're turned off in the BIOS? (Hey, it happened to a friend of mine!) If the USB *should* work (according to the BIOS), but doesn't, then we can safely conclude that it's fucked up... Whether an USB driver will fix your problem is debatable. I've got an ASUS P4P800 (cool), and it needed USB 2 drivers (SP1); It had fully functional USB ports, but Windows simply didn't understand that they were actually USB 2.