Just been to see a client this week that had a problem with his USB stick. It worked fine on his other computers but when he tried plugging it in to his home PC he would get an error pop up saying that one of the devices has malfunctioned and it would appear as unknown device in device manager.
I have tried several solutions including uninstalling all the USB devices in device manager and even reinstalling Windows to no avail.
It turned out in the end that the PC will not boot if a mass storage usb device is plugged into it so I realised that the problem wasn’t with Windows. I have tried resetting the Bios to defaults, that didn’t work either. In the end, I took the Bios battery out of the mother board, let it stand for a few minutes and voila! it all started working again.
Good luck if it happens to you…