Photoshop Elements won't open image

I'm having a strange problem with the PS Elements 9 software on my wife's mini mac computer. The program launches fine, and when I try to open a picture (any picture - I've tried lots) I get the various dialog boxes ("reading Photshop format", color mode conversion progress bar, etc.), but then no window showing the photograph. No error message. Also, none of the windows (info, history, layers, etc.) that I've selected show up. If I go to the file menu to "open recent", it lists the photos I've told it to open but have never seen.
I've tried uninstalling the software and then reinstalling it, but continue to have the same problem. It worked fine when I last used it several months ago. I have various other Photoshop software on my other computers (CS 5, CS 4) and have never had this problem. Any ideas? Thanks.

Mini Mac 4.1 (2.4 GHz Core 2 Duo, 2 GB Ram), OSX 10.6.8

Tom Valens
Forest Knolls, CA