Having worked in a call center for that stuff, I get why they asked if you have. They can't assume all callers are tech savvy. The jokes you hear about how it turns out the computer wasn't even plugged in? Those are true stories.
Hell, there was one woman who called in saying she couldn't get her computer running, and the tech spent nearly half an hour with her before finally asking her to check if the computer was actually plugged in. She asked him to wait a moment so she could go find a flashlight, because the power was out due to hurricane Katrina, and she couldn't see behind the computer without light...
Also, asking you to do it again once you've confirmed you already did it may seem a bit ridiculous, and can be annoying, but sometimes people say yes just to avoid that step, thinking they know that's not the problem.