I have a Mac and HP printer Photosmart D110, both purchased in 2009. I've upgraded software regularly.
I have been unable to print all day; this is a frequent problem, but I've been able eventually to make it work. Today, I decided to reinstall the printer to the mac. I have been unable to do that. The HP Utility continues to tell me the printer can't be found or the software isn't supported.

Any suggestions? The printer is online and working; the mac won't find it and now it isn't even showing up in the preferences.