After receiving an "unknown publisher" message on my Photoshop Elements 9 program, I uninstalled it and reinstalled it. The reinstallation froze on the update screen. The program would not reinstall. I have the serial number and am using Windows XP. Elements 4 has also been installed on this computer, but will not function now. Please advise.
Try copying the disk contents to a new folder on the dektop and then try to run setup from there.