Disable media source for any install
User Configuration\Administrative Templates\Windows Components\Windows Installer
Prevents users from installing programs from removable media. If a user tries to install a program from removable media, such as CD-ROMs, floppy disks, and DVDs, a message appears, stating that the feature cannot be found.
This policy applies even when the installation is running in the user's security context.
If you disable this policy or do not configure it, users can install from removable media when the installation is running in their own security context, but only system administrators can use removable media when an installation is running with elevated system privileges, such as installations offered on the desktop or in Add/Remove Programs.