v725w using USB, print error

After removing a paper jam, I replaced the print cartridges and reseated the printhead as indicated, a test page printed and I thought all was ok.  But when I try to print, it says print error, and in response to various fixes that I've tried (found online and through troubleshooting) I get messages indicating either that "the printer cannot respond" or "communication error", etc.  I've unplugged and re-plugged numerous times, both the USB cable and the power cable.  I've uninstalled and reinstalled the printer, the drivers, reinstalled the driver from the installation disk, updated drivers and software from the internet, ad nauseum.  Mechanically, the printer works, as I've seen test pages print twice now.  Yet when I initiate a print command I continue to receive a print error; then I delete it from the print queue and try again, and get the error again.  Any suggestions on how to fit it?  Thank you.