Won't Print - says jammed but isn't

When I try to print it says I have a paper jam in the output tray - which I don't (everything's been checked - I've even had the top off and find nothing). Also, when I turn on the printer, the resume light blinks 3 times (amber) while the power is solid green. I've looked in the manual - tried to get it into service mode to do test prints, etc. but no matter what I press, it always goes back to 3 amber blinks. I've had the printer for awhile and have never changed the excess toner holder - don't know if that might be doing it but I can't find how to remove the bottom and/or how to change it. Any help would be appreciated.