For a few weeks now, Windows has been unable to remember how to install drivers for basic USB class-compliant devices, such as mice, keyboards, or thumb drives. It would only allow devices to work if they were still plugged into the same port on the same hub where they last worked. Everything else would make it bring up the "found new hardware wizard," and everything in it would insist that there was no driver found, or that the driver I specified "did not match the hardware," or whatever.
But I appear to have found the secret to fixing this: when the "found new hardware wizard" comes up, tell it to search for the driver in c:\windows\inf (which is of course where Windows is supposed to search for it TO BEGIN WITH — oh and note that you can't browse to it, since it's a hidden directory for some reason), and then that seems to get everything back in order.
Of course, none of the billions of forum threads I've seen about this even remotely touch upon this issue. ARGH.