When you say you downloaded the latest software, was that the installation software? If so did you keep the downloaded setup.exe file?
Which printer model is it?
Was Windows 7 an upgrade or a new install?
If it was an upgrade did you leave the printer installed.
First thing to do is uninstall all the HP software.
Control Panel -> Programs and then click each HP item in turn and click to uninstall.
Once all has been removed, reboot.
Get the latest installation software from HP unlerss you still have the disk that came with the pronter.
Using either the software or disk, install and follow the instructions for when to connect the printer.
Being out of guarantee should not prevent you from getting support.
Answer the questions above and we can see if there is a better installer available for your printer for Win 7.
dave