Emily,
We need to rule some things out. Do the USB cables you're trying to use work on other "known to be good" devices? Do not reuse any cable(s) that doesn't work, even if new. Once you have a cable that has been proven to work, try connecting the camera to the USB port on the computer again. Make sure the camera power is OFF while connecting to the computer. Only after connecting should you turn camera power ON again. You can review the whole process starting on page 147 of the
manual.
If it doesn't work, it is possible that the ports you're trying to use is either 1) defective or 2) overloaded. Try connecting to a different USB port on one of the computers. If you don't have another USB port, or if it still doesn't work as expected, remove all the devices connected to the USB ports that are not needed to operate the computer. This will lower the amount of power the computer needs to supply to USB devices (some - but not all - computers will flash a message on the screen if there's too many devices connected). Reconnect the powered off camera and try again after turning back on..
If you're still having a problem, suspicion turns to the camera's USB port. Resolving a problem within the camera will likely be the most expensive fix. It took considerable restraint, but I didn't even mention the other solution ;-)
I hope this helps & good luck! Please rate my reply - thanks.
