Camera went completely dead - removed the front cover and found a screw loose. Replaced it and the camera worked fine. This could be a problem for others.
Follow guide “Disassembling Canon PowerShot SD1100 IS Front and Rear Cover”
Check inside camera for loose screw from this location (indicated by yellow arrow). Return the screw to location and firmly tighten it. Reposition and tighten the covers. Problem solved!