I just wanted to let you know that your issue was not the same as the one you'd originally posted in, so I branched you off, changed the topic, and gave you your own thread to get more moderator notice.
I'll do a little research and see if anyone else has reported this and get back to you. In the meantime, if any of the other mods has any ideas, please post them here.
I have found the both the software and customer service lacking for both these companies. I have an HP Printer too and, at the moment, running McAfee Virus software. I have got my printer working mostly on my network. I was wondering if you had opened up the UDP and TCIP port using McAfee's Securitty Center. Click on firewall until you see a link for settings. Then choose Ports and System Services. You should see some ports open for TCP/IP and/or UDP for your printer.If not you might try searching HP and McAfee's sites for port setting for your specific printer model. I don't remember where I found the setting for my, but I am pretty sure I found them online. (It might actually have been on HP's site) I have a different model than your's so I don't know if the settings are specifice for the software and printer.
The Other issue I had was making sure that the printer's wireless antenna was on. HP has offered several updates to the printer's software both for the computer and firmware for the printer that had to be uploaded to try and get the printer to be found on the network. I've had the printer for a year and a half maybe a little longer and each update has improved the functionality a bit. Though it could still be better.
I have an OfficeJet 8500 All-In-One printer. I never have problems printing after the printer has gone to sleep, but scanning and faxing are almost impossible once it has. It always seems to take a long time to get the documents ready for either of these functions and by the time I am ready, the printer is asleep and difficult to wake up other than for printing. And, of course the printer is upstairs and I am usually downstairs. I have found though, that the easiest way to get up and working again (turning the printer off and on again takes way to long 'cause it always wants to test the jets and doing a network test causes you to waste paper and ink when it prints it's report) is to go into network settings and turn off the antenna and then turn it back on. It will then be awake to be able to use the software on the computer.