HP deskjet 648c will not print

Remove your printer from the PC and uninstall the printer software. Now reinstall the printer software and connect the Printer to be detected and installed. Check printer properties to see the ink levels.
Use head cleaning before a test is taken . It is possible that the head is not reacting to the need of the command , can be an issue with ink drying , can also be poor ink cartridge contacts. If this wont get the printer working it can be fault in the printer's motherboard.

I supect you have a driver problem.
1) Uninstall/delete your existing driver.

2) Go to the following link at the hp website and download the driver and install as instructed:
http://h10025.www1.hp.com/ewfrf/wc/softwareDownloadIndex?os=228&softwareitem=dj658en&lc=en&dlc=en&cc=us&lang=en&product=60402

lexmark z515 program to download in my computer

test page printing but doc files not printing....

HP DeskJet 6940

one of your staff addressed it completely via chat

Just a suggestion: Have you tried using a different ink cartridge? I have found brand new cartridges to be bad right out of the wrapper.

Probably a problematic parallel cable, or reinstall drivers...

Check to make sure the USB/ serial cord is plugged all the wat in on the back of the computer tower and the printer itself.

Here's a great link for troubleshooting you need to do for your printer: http://h10025.www1.hp.com/ewfrf/wc/document?docname=bpa00226&lc=en&cc=us&dlc=en&product=60402&rule=28651&lang=en

Do you have the installation disk for either printer? If so simply reinstall over the existing ones. If you do not- Go to Start/printers and Faxes Clcick on install new printer. Select from list Select make Select model select OK