I have a Dell XPS 400. The device manager thinks that all the USB ports are working fine. However, if i pug anything in it is not recognized. We tried to roll back the usb port drivers and it said that they have never been backed up. We tried to update the drivers and it said there was nothing better available. I have 5 ports in the back and if you plug anything into them then it locks the system up. The two in the front just gives an error message.