Usually I just humour them. I can't be bothered to go through the same motions that I just went through with some guy on the phone. I just start giving them messed up answers and listen to them sputter and stammer trying to find the line in the script that tells them what to do next.

Them : "Has your computer finished rebooting?"
Me : "I just got an asychronous i/o overflow error"
Them : "Hmmmm. Maybe we should send you another hard drive."
Me : "If you think I need it."