To Enable/Disable USB in Windows

To disable the access to USB port, in Windows OS

1. Click Start, and then click Run.
2. In the Open box, type regedit, and then click OK.
3. Locate, and then click the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\UsbStor
4. In the right pane, double-click Start.
5. In the Value data box, type 4, click Hexadecimal (if it is not already selected), and then click OK.
6. Quit Registry Editor.
To re-enable a disabled port:
1. Click Start, and then click Run.
2. In the Open box, type regedit, and then click OK.
3. Locate, and then click the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\UsbStor
4. In the right pane, double-click Start.
5. In the Value data box, type 3, click Hexadecimal (if it is not already selected), and then click OK.
6. Quit Registry Editor.