Which end is which?
Customer: "I'm no computer whiz, but I was wondering which end of the phone cord goes into the wall and which one goes into the modem."

Another satisfied AOLer
A man called, and he was EXTREMELY upset. He was yelling and carrying on, very angry with his last ISP. He wanted to know our prices and services, so as always I told him what we offer and what we could do for him.
Customer: "Well, good, I'll go with you. I was using that *^@#$%ing AOL, and I hated them &^$@#%*s!"
Tech Support: "What was the problem?"
Customer: "Well, EVERY single time I signed off AOL, this smart-@$$ guy kept telling me 'goodbye' in this smart-@$$ tone, so I canceled them!"
It was really painful to repress my laughter.

Computerless (and clueless) Internet
I work for an ISP. One day a woman called, furious.
Customer: "I bought the Internet the other day, and it ain't workin'."
Tech Support: "Well, ma'am, can you explain what's happening?"
Customer: "Well, I called that number that you gave me, and it don't do nothing."
Tech Support: "What do you mean?"
Customer: "When I call it, all it does is squeal in my ear!"
Silence.
Tech Support: "Ma'am, do you have a computer?"
Customer: "Computer? Hell, I pay you twenty dollars a month! I don't need a computer!"

More uses for the floppy drive
Tech Support: "Ok, sir, to finish opening your account, I will need you to provide a credit card number."
Customer: "All right, hold on."
[some rustling sounds]
Customer: "Ok, do you have it yet?"
Tech Support: "Well, no, You haven't given it to me yet."
Customer: "Sure I did. I just stuck it in this slot in the front of this computer."

Possible remedial English student?
Customer: "I can't log in to my account."
Tech Support: "Ok, let's look at your configuration."
Customer: "Ok...but I know that my User ID is case sensitive."
Tech Support: "Yes it is. Ok, what does it say in the 'User ID' field?"
Customer: "'Case Sensitive'."

Not quite clear on the concept
Customer: "If I want somebody to send a reply to my email...should I include a self-addressed stamped envelope along with it?"

It's right next to the "Any" key
Tech Support: "How may I help you?"
Customer: "I'm writing my first email."
Tech Support: "Ok, what seems to be the problem?"
Customer: "Well I can get the 'a'. But how do I put the circle around it?"

Phantom Menace!
One customer kept reporting a problem with her system beeping at her. This would happen (at times) without a user at the computer and at no specific times. The random timing, of course, made the troubleshooting difficult. Our decision was to create a problem report and have her call in when it was occurring or had occurred.
One month later, she called back. It turned out that a pager had been dropped under the desk where the computer was situated. (I actually had a call like this - the pager was in a drawer and was emitting a "low battery" warning!)

It's a case of phonetics
I once had a woman call and ask if we also taught "DON'TS" in the "DOS" class, and she was dead serious.

Bilingual?
I was giving instructions to a caller once, but his son was the one physically sitting at the computer, so all my instructions had to be relayed. Here's a snippet of the conversation:
Me: "Click on 'start', then select 'shut down', then select 'restart in MS-DOS mode'."
Customer: (to his son) "Ok, press 'start', 'shut up', and 'sit down'!"
The really scary part was what his son said then:
Customer's Son: "Ok, I'm at the C: prompt!"
Do we really want to know what goes on at that house?

This guy needs a sign!
Customer: "Why didn't you tell me I have call waiting?"
Tech Support: "Sir, we have no way of knowing if you have call waiting."
Customer: "Well, you should ask everybody!"
Tech Support: "Do you have call waiting?"
Customer: "What's that?"

Beam me up, Scotty!
I once had a customer call me up wanting to send something via email. She said no matter what she did it wouldn't go through. After much debating over the settings, I finally asked her what she was trying to send. It turned out she was trying to email a box to her daughter for her birthday. I still haven't quite figured out how she thought that would work.