prevent users from writing to usb

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