Unplug the network cable and reboot 3 times in a row.
Or do the method Gabiene supplied in your duplicate post
We have been using this printer for the past 1 year in a network environment with about 30+ employees. Recently one of our employ tried to print a PDF document consisted of 1 page. After printing the document is still on the job queue. When we tried to delete it, it shows "processing" and it stays like that. Now we are unable to print anything from direct print or using web interface. And when ever we restart the printer page prints and it stays in the queue. I have tried to upgrade the firmwire via web interface but it does not work. I have also tried to do fractory Reset and it also does not work and the print job is in queue. So please help me !!