First, try checking your USB connector and make sure it's working ok.
Second, Right clicking (Computer) then click (Manage) click on (Device Manager) check under (Portable Devices) if your Canon camera is listed. If it's listed then it recognises it. If not, unplug your camera and uninstall any Canon camera software you’ve installed then reboot. Plug camera back with USB connector and see if the computer recognise the device and try to install a driver. If it’s successful, you’ll be able to see autoplay popup for Canon Digital Camera.
However, trying to control the camera using the canon utility may not be possible; the software I think is not compatible with Windows 7. For that you need call Canon for support.