I've just found this on another website as lots of HP users are complaining about this.
"I figured it out! After lots of button pushing and forum reading, I figured out how to make my HP Envy 4500 allow compatible non-HP ink cartridges.
With the refurbished cartridge out, go to "Tools" and scroll down to "Restore to Default" and click "OK".
After that you should be good to go! Insert the Cartridges, do the alignment and it's as good as new"
If you want the website, it's here
http://h30434.www3.hp.com/t5/Inkjet-Printing/Using-Non-HP-Ink-Cartridges/td-p/1759353/page/2