Canon SC100 Lens Error
I have a 3 year old Canon PowerShot SX100 IS. While testing an external battery power supply I built, the external power connector pulled out while the lens barrel was extending just after I turned on the camera. Power to the camera was lost before the lens barrel fully extended and wouldn't reset when I repowered the camera. The dreaded error message "Lens error, restart camera" appeared and the camera shut down. I restarted the camera over and over and over again but the lens wouldn't reset. I was extremely lucky to find the information here and read various fixes. I didn't want to take the camera apart so I tried various fixes others have successfully used. I first tried smacking the bottom of the camera hard with the palm of my hand just after pushing the on/off button but that didn't work. The one which worked was smacking the camera on the side immediately after I pushed the on/off button. I smacked it quite hard twice with the palm of my hand then, suddenly, the lens barrel began to move and the lens reset itself back to its starting position. Thanks to everyone who has posted here!