I am trying to help a friend get her printer working again. It's an HP Photosmart C4780 on OSX 10.4, working wirelessly, and she says it was working fine until one day it won't print. She tried uninstalling it, etc...no help. I started over from scratch using USB and the driver from HP.com. The software starts up and gets to the install screen, but nothing happens when I click install. The button looks like it clicks but nothing ever happens. Any help would be appreciated.