I've been looking around lately on Amazon and Ebay for some good deals on Photoshop CS2 and i've seen several that say they are used. Now I assume that by used they're saying they have installed it in their computer. And now i'm wondering that if a program has been installed in one computer can it still be installed in another? I'm asking this because I've recieved some programs from family and tried to install them into my computer and it didn't work because it had been previously installed in theirs. I hope I am making sense here. Any help is appreciated.