Your OS may have updated and not provided the driver for the camera. Try any or all of these steps that apply to your situation.
Here are the steps to take.
1. Establish whether or not you have
a connection between your camera/computer by going to your start
button, control panel, system, hardware
tab and device manager. The camera must be powered on and in playback
mode (should automatically go to playback mode when connected, camera's
screen should go black if there is a connection). Make sure you have a
fully or nearly fully charged battery in your camera.
2. Once in
device manager, look under Imaging Devices. If your camera is properly
connected it should show up as Canon Powershot SD800. If it shows a
yellow exclamation point, there is a driver issue, and even if it
doesn't show a yellow exclamation point, you may want to update your
driver anyway by right clicking and having the system search
automatically for driver updates. If download of driver begins,
great...once finished, restart camera and your problem may be resolved.
3. If there are any other imaging devices, you may have to temporarily disable them to avoid conflicts.
If you have any other imaging software running, exit or close the
program in your system tray (down by your clock in the right hand
corner of your computer's desktop.
5. Try again to connect.
If you are on a desktop, try a rear usb port vs. a front port. You can
also try a different port on a laptop. After each change, try
restarting camera to establish connection.
7. Go to start/My
Computer and look for the icon for your camera...you will be able to
download images even without Canon software loaded onto computer so
this is not a software issue if you have no hardware connection. If you
see the icon, right click on it and choose Get or Import pictures. From
there the default Microsoft scanner and camera wizard should launch and
you will be able to import your images.
8. If still no
connection, try going to Start/Run and type in services.msc here you
are looking for 4 services to be running. Check under status of each
service and make sure it reads that each of these services are started.
- Canon Camera Access Library 8 (if Canon software loaded)
- SSDP discovery service
- Universal Plug and Play Device Host
- Windows Image Acquisition
Once all of these
services are started on your computer, restart camera once again. If
any of the last three services are not on your computer or are not
started, connecting will be a problem.
If all of these steps fail, try purchasing an SD card reader from your local electronics store for around $12 and download images from there. Canon also offers lifetime technical support for your Powershot, so give them a call if none of these steps work or if you would like someone to walk you through it.
Best of luck to you!