Many IT professionals bemoan the apparent lack of computer knowledge in the users they support or otherwise provide services for. Not even ten years ago, I agreed with that - users should know more about the equipment they are using.
However, this is no longer ten years ago. This is the age of the $400 laptop PC, the smartphone and tablet. And the "wearable". Computers have transitioned into the status of an appliance, like a TV, refrigerator or car.
Auto mechanics don't expect their customers to be able to service their cars, appliance repair service techs don't expect customers to fix a refrigerator, why should we IT professionals expect our customers to be able to diagnose a system crash or upgrade hardware? Just like their cars, refrigerators, and microwave ovens, people just expect them to work, and have a professional fix it when it breaks.
Operating one, however, that's a different issue. Anyone using one definitely should be able to correctly operate a computer. I don't expect my users to be able to install a printer, but they really should be able to select the printer from the list.