I think, you are already known if USB Drive is one of the most effective tools to stealth data. Just plug it in your USB port; computer will recognize it as a new drive and then you just need to drag and drop files or folders to your USB drive icon. And your files data have been moved. That’s it… so simple. If you want to prevent your data from stealth activity, just prevent every plugged USB drive to have write capability. Or, write protect it.

By default, Windows XP doesn’t provide any tools to protect plugged USB Drive to have mode read only. But you can do it through Windows Registry.
1. First, open the Registry Editor by click Start -> Run, enter regedit in box and then press Enter.

2. Navigate to registry path: HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Control.

3. Right click Control key, click New -> Key menu.

4. Give a new key: StorageDevicePolicies and then press Enter.

5. Right click StorageDevicePolicies key, click New -> DWORD value menu.

6. Give it the new value with name: WriteProtect.

7. Double click WriteProtect value, give it value1 and then click OK button.

8. Close Registry Editor and then restart your computer.

9. Try to copy a file to your USB Drive, if you did it right, you’ll get a write protect message.

If you want to remove read only mode to your plugged USB drive, just delete WriteProtect value or give it value: 0.