How do I lock DVD drive from Win7 user accounts? (1 Viewer)

I have to do a little Windows 7 administration, which I'm learning on the fly. I'm stumped on how to lock all external media drives from normal user accounts (DVD, memory card, USB ports, all of it). But I still need them active for the Administrator accounts.

A quick google doesn't find it; I'm probably not searching the right terms but which reinforces that I'm ignorant on this task

You're probably tempted to suggest I ask my corporate IT. Suffice to say I don't have such an expert handy. Not that I've found.

I'd appreciate any help on this. Thanks!

Also: I understand I can disable it completely, as with this video. That will do, if that's the only way. But I'd rather it be disabled for all normal user accounts, and enabled for administration.