Hello Ross-WM,
Welcome to the HP Support Forums! :) I understand the HP digital imaging monitor does not start, you are still able to print and scan with your PSC 1315.
Did you ever have another HP printer installed on this computer, do you get any error messages on the computer regarding the HP digital imaging monitor?
I would like you to start here and run the HP Print and Scan Doctor- It was designed by HP to provide users with the troubleshooting and problem solving features needed to resolve many common problems experienced with HP print and scan products connected to Windows-based computers.
I will watch for your reply.
Thanks,