Hi nintendoboy15,
I understand you have a Deskjet D1460 that is no longer showing up in the HP Solution Center, although your Photosmart B209a does. I'm sorry to hear this, but I will definitely do my best to assist you!
I believe the issue is due to the two printers having two different versions of the same software. The B209a uses version 14 of the Solution Center software while the Deskjet uses version 13. The two can work together, but generally the older software has to be installed first and then the newer software for everything to work.
At this point I believe your best route is to follow this Uninstalling the Printer Software document to remove the software for both printers. Once that is removed you will want to install the Deskjet D1460 first and once that installs successfully you will want to install the Photosmart B209a. I would also recommend that you download the software for each to make sure you're getting the most up to date software (which you can do by clicking each printer name in blue in the previous sentence).
Hope this helps, have a great weekend!!