Canon powershot A470 problem when i click photo

Go to the menus and find the set to default option.
This should reset the menus and options to original.
Go to the menu section find a setting something like this... such as.. reset all to default or set to factory default or simply RESET.

Check to see if the pictures are saved to the card by taking a picture, then remove the card and play it back in either another camera or use a card reader to read the card.

If these tests shows that no picture was taken or it is all white, then the camera needs repair or has a ccd problem.

Another option is to call Canon Repair at the following page and use the 800 number for calling the repair department.
Canon has a trade-up or trade-in program which is a great way to get another camera at a good price. Canon will allow you to trade in your camera for a reasonable price against a refurbished camera plus a cost which is reasonable. A refurbished camera will come with everything it had when new, and will have been restored to original specifications.