|I experienced the same with my Canon Pixma iP 3000. What happened was: I took the printer to a service because it had some ink cartridges issues. When I returned and reconnected the printer to my computer I tried to have it print a test page. The answer was "Error 5100" with the same message "Turn off then on and see if it works."|
What I did was "Printer" --> "Properties" --> Maintenance --> Custom settings: I checked the box for "Align heads manually", then clicked "send". This solved the "error 5100" thing.
My guess is that since the printer had been connected to another computer (at the service centre) it may not have recognized or remembered its settings back home. And since the "Print check alignment" didn't work, nor did the "align head" command from the printer front, I had to do this.
Hope this helps.