I have a canon printer and it says paper output slot is jammed and we don't have any paper jammed?

WEll, take it apart and look for tiny paper shreads stuck somewhere...then unplug power for at least 60 sec. and try again.

I had this same problem with my pixma mp490 and accidentally got it to work again. instead of choosing print from the computer screen i pushed the buttons on the printer itself that says start then a button under black and under color. i pushed em both and it started printing and i havent hadnt any more problems printing the usual way since then. hope this helps