Here's another really old one...
Someone calls the WordPerfect tech support line.
CUSTOMER: "WordPerfect isn't working."
TECH SUPPORT: "Tell me what you see on the screen."
CUS: "The screen is completely blank."
TS: "Are you sure the monitor is turned on?"
CUS: "Yes."
TS: "What about the computer? Is that turned on?"
CUS: "Yes, I turned it on just like I do every day."
TS: "Ok, maybe the plug came out. Can you look at the power cord from your computer and trace it to the outlet to see if it's plugged in?"
CUS: "No, I can't do that."
TS: "Why not?"
CUS: "It's too dark to see behind my desk, because there's a power outage and the lights are off."
TS: "Oh, okay. Here's what you need to do. Pack up your computer and bring it back to the store where you bought it."
CUS: "Really? Is the problem that bad?"
TS: "Yes."
CUS: "What do I tell the guy at the store?"
TS: "Tell him you're too stupid to own a computer."