Ok so don't hate me here, but I used to do tech support for Comcast. You need to unplug your modem and router from the ac outlet. Plug your modem in first and let it fully boot up...2-3 minutes. After that plug the power to your router back in. That's the proper way to power cycle. That should do the trick. Do you have other devices in the house that is wireless? Are they working?
Spoken like a true cable tech support person. It must take about 5 minutes to train you guys, since that's the only thing they have to teach you.