USB en & dis

As always - back your system up before messing around in the registry.

Just open regedit and browse to this key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\UsbStor

Notice the value 'Start'

Switch this value to 4, and USB storage devices are disabled.

Switch this value to 3, and USB storage devices are enabled.
To disable the access to USB port, in windows XP and 2000, follow the steps below
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, follow these steps below
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.