Why my canon powershot camera is not working?

In your question, you have not mentioned any proper lead. So, it assumes that your camera is not synchronizing with the flash. As you press the shutter release button and the flash light clicks. But the shutter gets lock at the time of the shutter button release. So, your picture is not coming to the CCD sensor and does not record anything. It is a common problem for any camera whether it is digital or analog. So, it is better to visit the local camera repair shop and get repaired your camera. Sometimes, it observed that if you are not using your Canon Powershot camera for long time, then the condensation in the inside of the camera may lock the shutter which may be the main reason for your camera problem. So, it is better at least if you release the shutter once in six months, then your camera will not face this type of problem anymore. The effect of condensation is very harmful for the electronic circuitry of the digital camera. Because, the traces of digital circuitry get damage due to interrupting flow of the current to the base. As, it happens only for the condensation. So, next time when you will use the camera as you should make a habit to use it frequently at least once in six months. It will save your camera and it also saves your money & time.