By default, Group Policy does not offer a facility to easily disable drives containing removable media, such as USB ports, CD-ROM drives, Floppy Disk drives and high capacity LS-120 floppy drives. However, Group Policy can be extended to use customised settings by applying an ADM template. The ADM template in this article allows an Administrator to disable the respective drivers of these devices, ensuring that they cannot be used.

Import this administrative template into Group Policy as a .adm file. See the link in the More Information section if you are unsure how to do this.
 
CLASS MACHINE
CATEGORY !!category
 CATEGORY !!categoryname
  POLICY !!policynameusb
   KEYNAME "SYSTEM\CurrentControlSet\Services\USBSTOR"
   EXPLAIN !!explaintextusb
     PART !!labeltextusb DROPDOWNLIST REQUIRED
 
       VALUENAME "Start"
       ITEMLIST
        NAME !!Disabled VALUE NUMERIC 3 DEFAULT
        NAME !!Enabled VALUE NUMERIC 4
       END ITEMLIST
     END PART
   END POLICY
  POLICY !!policynamecd
   KEYNAME "SYSTEM\CurrentControlSet\Services\Cdrom"
   EXPLAIN !!explaintextcd
     PART !!labeltextcd DROPDOWNLIST REQUIRED
 
       VALUENAME "Start"
       ITEMLIST
        NAME !!Disabled VALUE NUMERIC 1 DEFAULT
        NAME !!Enabled VALUE NUMERIC 4
       END ITEMLIST
     END PART
   END POLICY
  POLICY !!policynameflpy
   KEYNAME "SYSTEM\CurrentControlSet\Services\Flpydisk"
   EXPLAIN !!explaintextflpy
     PART !!labeltextflpy DROPDOWNLIST REQUIRED
 
       VALUENAME "Start"
       ITEMLIST
        NAME !!Disabled VALUE NUMERIC 3 DEFAULT
        NAME !!Enabled VALUE NUMERIC 4
       END ITEMLIST
     END PART
   END POLICY
  POLICY !!policynamels120
   KEYNAME "SYSTEM\CurrentControlSet\Services\Sfloppy"
   EXPLAIN !!explaintextls120
     PART !!labeltextls120 DROPDOWNLIST REQUIRED
 
       VALUENAME "Start"
       ITEMLIST
        NAME !!Disabled VALUE NUMERIC 3 DEFAULT
        NAME !!Enabled VALUE NUMERIC 4
       END ITEMLIST
     END PART
   END POLICY
 END CATEGORY
END CATEGORY
 
[strings]
category="Custom Policy Settings"
categoryname="Restrict Drives"
policynameusb="Disable USB"
policynamecd="Disable CD-ROM"
policynameflpy="Disable Floppy"
policynamels120="Disable High Capacity Floppy"
explaintextusb="Disables the computers USB ports by disabling the usbstor.sys driver"
explaintextcd="Disables the computers CD-ROM Drive by disabling the cdrom.sys driver"
explaintextflpy="Disables the computers Floppy Drive by disabling the flpydisk.sys driver"
explaintextls120="Disables the computers High Capacity Floppy Drive by disabling the sfloppy.sys driver"
labeltextusb="Disable USB Ports"
labeltextcd="Disable CD-ROM Drive"
labeltextflpy="Disable Floppy Drive"
labeltextls120="Disable High Capacity Floppy Drive"
Enabled="Enabled"
Disabled="Disabled"

For more information about applying Administrative Template files, including instructions on how to use the above template, download the Microsoft White Paper 'Using Administrative Template Files with Registry-Based Group Policy' from here.
 
http://www.microsoft.com/downloads/details.aspx?FamilyID=e7d72fa1-62fe-4358-8360-8774ea8db847&displaylang=en
 
This template is considered a preference rather than a true policy and will tattoo the registry of client computers with its settings. If this template is moved out of scope of the Group Policy which applies it, the registry changes it makes will remain. If you wish to reverse the settings made by this template, simply reverse the options to re-enable the drivers.
 
Preference settings are hidden by default in the Group Policy template editor. When applying this template, follow these instructions to change the view settings that allow preferences to be viewed.
 
http://www.microsoft.com/technet/prodtechnol/windowsserver2003/library/ServerHelp/e50f1e64-d7e5-4b6d-87ff-adb3cf874365.mspx