os.listdir() takes a string that is a directory. "my computer" is not a directory. C:\ displays in my computer is, D:\ also is, your camera also is, but not "my computer". So attempting to list the directory of a non-existing directory (my computer) is a dead end.
I was going to test this and play around with the idea to get a little more info for youhttp://stackoverflow.com/questions/4666 ... -connected
but then i realized i already deleted my windows OS from all my computers and i didnt want to modify the windows 7 virtual box running in linux to accept usb's and such. So i will just leave you with the link.