My Canon Sd1000 will not take pictures. You can

A stuck shutter is another common failure mode for digital cameras. The symptoms of a stuck or "sticky" shutter are very similar to CCD image sensor failure. The camera may take black pictures (for shutter stuck closed), or the pictures may be very bright and overexposed, especially when taken outdoors (for shutter stuck open).

To confirm a stuck shutter, put the camera in any mode other than "Auto", and turn the flash OFF (you don't want to blind yourself for the next step). Next look down the lens and take a picture. You should see a tiny flicker in the center of the lens as the shutter opens and closes. If no movement is seen, then you likely have a stuck shutter. If so, please see this link for further info and a simple fix that may help.

Note that your camera does not have shutter priority mode (Tv) as listed in the link. Instead, put the camera in manual mode and turn off the flash, and also turn off the LCD display (press the DISP button). With these settings, try the fix in a darkened room, opening the battery door immediately after taking the picture. Give it several tries, if no luck consider also trying step 5a described in the link.