Wireless Canon printer problem - solved

My household has 2 MacBook Pros that suddenly stopped being able to print to my Canon MX870 printer/multi-function device wirelessly ("Support code: 300" was the error message I got). After many hours of the chicken dances of turning things off and on (modem, router, Mac, printer, etc), and lots of other attempted solutions,* I found one place on the Canon support webpage that said to try UNPLUGGING the printer for at least 10 seconds to actually re-set it. Folks, this solved the problem, at least for the moment. Hooray! *One other solution I tried was replacing some of the ink cartridges. Apparently, they can appear to be dry even with ink in them (esp. if you haven't used the printer in a while -- and I also live in a fairly dry climate), and in some cases as stated elsewhere in the Apple support community, that dryness can cause a communication problem for the printer. That didn't solve it for me, but I offer that in case it might work for you.