Built in Flash Problem
Ray UK wrote:
Sounds very much like a battery problem, popping up the flash causes it to draw extra current and the battery can't cope, the voltage drops so the camera turns off.
Try another freshly charged battery.
Or if the main battery is a couple years old, get a new one. The batteries wear out with time and won't hold enough charge, even if the charger indicates 'full'.
Unapologetic Canon Apologist