PLEASE HELP with HP Officejet Pro 8500A all in once printer

[shatterdsky]

so we have a HP Officejet Pro 8500A for about a year now and when we first took it out from the box we got it to work right away and installed HP ePrintcenter and other software tht it came with. we also got it to print from our iphones and ipads.  and then about few weeks ago the printer keeps saying offline even though i checked the printer's wifi connections it says its connected. i tried turning the printer off and then on again to see it solved the problem but nothing. it also has a error message on the home screen that says HP digital fax error and i dont know how to remove it. i tried fixing it using the eprint software that was installed on the Vista 32-bit desktop and an error pops up saying something about the firewall blocking it so i went to look at the firewall settings and nothing has changed. this printer is giving me a headache already even tho i reseted the network settings to factory settings still wont connect to the computer via network. i tried going to Setup - Web Service setup  it said it hasnt been enabled so i pressed continue and it said it needs a proxy address...i dont know where to get that proxy address....PLEASE HELP i need to get this printer working again for college

[Binary_Zen]

Try using the Network Diagnostic Utility. It should tell us if there is a connectivity issue with the printer. 

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c02037530