To block all the storage device in your Windows, run registry editor by typing regedit in RUN command.
In the registry editor, at left side navigation pane, navigate to following location:
HKEY_LOCAL_MACHINE > SYSTEM > CurrentControlSet > Services > USBSTOR
Now at the right side double click on START.
To block USB storage Medias, change the value data to 4.
If you want to unblock USB storage Medias just navigate to the same location and change th value data to 3.
that's all....make ur PC safe....more tricks to come....rep n reply if u like