"Printer offline" I cannot print from any device on the network directly to the printer as it always throws up the error, "Printer offline". I can only print to it using Google Cloud Print which is very frustrating. I have tried every suggestion from HP and nothing will allow me to change the status to online. Any ideas???

SOURCE: My HP 640 will not print. Ran the test, no print.

If these are new cartridges, make sure you removed all of the protective plastic wrap that comes when packaged.  usually its red , yellow or orange plastic tab that should be removed.
If these are not new cartridges, you may need to try another set. 
Try running the head cleaning utility under the printer utilities options HP is very good at having this utility available to trouble shoot most common problems.  If you don't have this utility, try updating your printer driver. (basically uninstall the printer and download the driver from the HP website, and reinstall the printer using the latest driver).
Hope this helps..
~enov8

SOURCE: My fax machine stays on and I can't print

Hello,
Try this.. Go to start, devices and printers and you will have a few things listed in there that are related to your printer. Most likely it will say document writer, fax and your hp printer. Make sure that the check mark is on your printer, not your fax. This indicates what your default printer is. To change this, right click on your hp printer and select set as default printer. Once this is set try printing again. Let me know if this works, if not we will try step 2. Hope this helps!