应该是系统USB 驱动 corrupted, 先清干净再重装

you can test it by plugging in your u***** movile disk to other computer and see if it is recognizable. If it is, then you don't need to reformat the disk, otherwise you need to repair the disk. To reinstall the system u***** port driver, you'd better use driver backup utilities CD that usually come with your purchase of the system.

It should be noted that removing an u***** disk you need to stop it first, otherwise it will corrupt the driver and make it unrecognizable in the system.