Hi,First, double check and make sure that you are using your original cable that came with the camera.The recent security updates to the Windows operating system and virus protection programs interfere with the camera connections. I have seen many cases where the connection worked one day and would not work the next. Some manual set up may be required to get the camera to connect, even with the Canon software installed.Now, restart your computer. Then with the camera on and connected with the usb cable,on the computer, go to [Start] control panel, ( In Windows 7 select show all options) scanners and cameras and try to connect through the wizard. The last part of the Wizard should give you the option to choose the program to open when the camera is plugged in. If scanners and cameras does not show in control panel, click Start and in the search box, at the bottom, type in scanners and cameras and hit Enter. This should take you to the scanners and cameras box.If unsuccessful, the last place to look is in the device manager. Go to back Control Panel, double click the System icon and select Device Manager. Under the heading Imaging Devices you should find the camera, possibly with a yellow triangle with an exclamation point. Click on Imaging devices (the words will highlight), then go up and click on Action and select "scan for hardware changes". The camera may then appear under the heading. You can also delete it and allow the computer to try to provide the correct driver. Since you are trying to use the Canon software, open the program and try to connect. You will now need to back through the Camera & Scanner Wizard to make it Auto launch. See below if you have Windows 8Now, restart you computer once more. Then with the camera on and connected with the usb cable,on the computer, go to control panel,
In Winndows 8
Open Control Panel by swiping in from the right edge of the screen, tapping Search (or if you're using a mouse, pointing to the upper-right corner of the screen, moving the mouse pointer down, and then clicking Search), entering Control Panel in the search box, tapping or clicking Apps, and then tapping or clicking Control Panel.
Control Panel has familiar settings like themes and desktop backgrounds, Family Safety, screen resolution, and more.
Swipe in from the right edge of the screen, and then tap Settings.(If you're using a mouse, point to the upper-right corner of the screen, move the mouse pointer down, and then click Settings.)
In the Settings charm, you'll find settings, help, and info for the app you're in, plus a few common PC settings—network connection, volume, brightness, notifications, power, and keyboard. These PC settings are the same no matter where you are in Windows, but the app settings are different in every app.
If you're not sure where to find the settings you're looking for, you can search your PC.
Swipe in from the right edge of the screen, and then tap Search.(If you're using a mouse, point to the upper-right corner of the screen, move the mouse pointer down, and then click Search.)
Enter a word or phrase in the Search box, tap or click Settings, and then select from the list of results.