Lock your USB port

To do this you have to make a registry tweak taht will prevent writting to the usb port in Windows XP.
1) Go to 'Start|Run' and type 'Regedit'.
2) Navigate to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control.
3) Here add a new folder on the left pane by right clicking on it and selecting 'New|Key'.
4) Name this folder 'StorageDevicePolicies'.
5) Click this new folder and in the window on the right create a new DWORD value, lebel it WriteProtect, give it a value of '1'.
6) Now users will not be able to write any data on the USB.