How Disable/Enable USB port:

1. Goto run
2. Type 'regedit' without quotes
3.Click on HKEY_LOCAL_MACHINE
4.goto SYSTEM
5. Click on CurrentControlSet
6. Click on services
7. Goto USBSTOR
8. Double click on 'Start' where value is 3
9. Now change the value data with 4
10. Now press ok and refresh your desktop your USB port is disabled, to enable the usb port replace the value 4 with 3.