I have a Dell 3100 cn laser printer. recently I started receiving an error message: 004-321, Restart Printer. I have to pull out the lower tray and remove a sheet of paper that has been pulled up into the printer, causing a paper jam. The paper is easily removed from the back portion of the lower tray area. Also, the colors have started to not align well. I took all the color cartridges out and cleaned the area . It seemed the black cartridge was leaking as there was alot of black toner inside. After I cleaned it out, I still had the same problem. I then purchased 4 new cartridges, cleaned it out again, and it is still doing the same thing. I purchased a new Drum Kit within the last 6 months and that does not seem to be involved in this problem. I have opened all the doors and tried to blow out the dirt with compressed air. It seems that maybe this could be a bad roller or of course I could be WAY OFF. The printer is about 3 years old and has never had a problem. There is no warranty left. Any thoughts? I would really, really appreciate it.