USB flash drives,MP3 or MP4 devices are used everywhere in schools and offices by employees or students. This is sometimes harmful for computers when these portable devices are infected by viruses, even for people who try stealing useful data.
You can prevent this by disabling the USB ports on the Windows Registry Editor which takes some minutes...
To disable access to USB port
Click "Start" then click "Run".
type "regedit" to open Registry Editor, and then click "OK".