prevent users from writing to our usb or changing the files in it

Prevent users from writing to Usb

  

The following registry setting will prevent writing to usb in windows Xp.
Expand HKEY_LOCAL_MACHINE\System\CurrentControlSet\Contro l Add a new key and name it "StorageDevicePolicies".
In the window on the right then create a new DWORD value and label it Write Protect, give it a value of "1" and users can no longer write to USB drives.
Giving a value of "0" will allow writing again