Hi Maria,
The HP Solution Center software is available for your printer for Windows 7, the HP Printer Assistant s intended for later HP Products only.
If you connect the priinter with a USB, from the Control Panel select Devices and Printers.
Right click the shown P Photosmart Printer and select Remove Device, then unplug the USB.
Be sure not to connect the cable prior the installaton prompt to do so.
You may download and insall the HP Full Feature Software below, the software includes the HP Solution Center program:
Regards,
Shlomi