Asking Liberace to powder his own piano

A 'phone call from the Reference Library.

"The new PC in the Ref. office isn't printing," says Eileen.

"Are you getting any error messages or anything?" I ask.

"No, it just says 'Printer can't be found.'"

"Which printer is it set up to use?"

"I don't know."

"Which one should it be using?"

After a full minute's silence I blink first.

"I'll come up and have a look at it."

(The techies amongst you will have guessed that it's the printer on the Ref. desk and that for some reason somebody had changed the PC's settings to print to a non-existant printer.)