Canon Powershot SD 780 "No Camera Found"

Good Day Everyone!! I have a situation, I'm trying to fix a problem by connecting a Canon Powershot SD 780 camera to an iMac 10.6 for a friend. It works well with a PC and he told me that it worked for him before with the same OS with nothing new installed or updated. Every time I go to Camerawindow, I get the message "No camera found". I I checked hardware and it doesn't show up in USB, but other devices do. I switched to different USB ports and took some devices off the USB ports, still nothing. Has anybody ran into this problem or know what it is? Your help will be greatly appreciated it. Thanks in advance!!