Who turned on the "Stupid" switch?

I have this fancy title at work, sounds very impressive etc. But every now and then something happens to remind me that brain damage is everywhere. Take today for instance:

Caller: I am trying to install (insert program here) on 3 different computers and it just won't go. I type in the command that it shows in the directions, and it worked fine on my server, but I can't get it to run on the other computers. I get a message saying it can't find that file.
Me: Ok, let's try this. Look for MY COMPUTER on your desktop, and double click on that.
Caller: ok, did that.
Me: Do you see the D drive in here?
Caller: Yes.
Me: Do you see (insert program disc name here)?
Caller: No.
Me: Ok, can you open and close the CD drive on this computer?
Caller: The cd isn't in this computer.
(I pause for a moment.)
Me: Where is the cd?
Caller: In the other computer.
(I pause again)
Me: What is it doing?
Caller: installing the program on that computer.
(I am silently pounding my head upon my cube wall. I take deep breath)
Me: Ok, we need to put that cd in this computer for it to find the file you are typing in.
Caller: Oh, I can go get it, wait a sec..
Me: NO! Let it finish, then go get it and put it in this computer.

Ok, one looney isn't too bad. Except right after that I get Caller #2.

Caller: I don't understand the installation instructions, can you go over those with me?
Me: Sure.
(I proceed to go through the instructions, explaining what she will be doing and seeing.)
Caller: So I have to put the cd in a workstation, and it will tell me when to put the other discs into the server?
Me: Yes.
Caller: But I don't have a cd drive on my computer.
Me: That's ok, it doesn't have to be that workstation. Go to a machine that does have one.
Caller: None of my machines have a cd drive.
(We are doing an upgrade. They had to have installed the previous version using a cd. And these are pretty recent computers)
Me: Do you have (insert program here) installed an your other computers?
Caller: Yes. All of them.
(I am starting to hyperventilate here)
Me: Then at least one of those machines has to have a cd drive. Can you look?
Caller: I am going to have to call my tech to find out where he put them.
(I am stunned. Seriously)
Me: That sounds like a good idea.
Caller: I will call back when I know where those are.
Me: That sounds good.

See. I swear someone flipped the "Stupid" switch on and forgot to tell me.Geez