I insert a new battery and go to a party. I switched on the camera and after some time the camera asks to change the battery and turned off. Change the battery and the same thing happens. The camera worked perfectly for two years.

It's usually because you need to change the internal battery for a new one, very easily located next to the battery port, directly underneath pull it up and replace it with a new CR1220 and replace the batteries too just to be on the safe side

This happened with my Canon Powershot A470. I sent it back to he manufacturer and they said I was using the wrong batteries. Even though the camera is supplied with two alkaline batteries, they recommend using AA NimH rechargable batteries.

Cross check that the batteries u inserted are compatible with the camera.

Hope this helped sir..

Your problem may be due to corrosion on the battery contacts inside the camera which can prevent the full power of the batteries from flowing into the camera. Try this free fix before you do anything else: remove the batteries and wipe the camera contacts firmly with a dry cloth (heavy corrosion may require cleaning with a wire brush, steel wool, or sandpaper). Remove any residue that may have fallen into the battery compartment during cleaning, then wipe both ends of the batteries and place them back in the camera. This cleaning clears the problem about 90% of the time. If it doesn't work for you, the camera may have a problem that requires professional repair.

The backup battery needs to be replaced. This small button battery (CR1220) provides the power for your camera to 'remember' settings when you change or remove the AA batteries. Instructions for changing this battery are in the manual on page 191 (US version of manual).
You can view/download the manual here.

Clean the contact of battery terminal .

And Insert new batteries .
Try to use batteries which have high power for longer life.

Turn it off, remove the disk and turn it back on. I have several of these that do the same thing and this usally works. Once the battery meter lights up you should be able to insert the disk and switch it to auto. For some reason sometimes it doesn't like the disk inserted when it powers up.

Same problem. Fully charged main battery. In my case, I hadn't used the camera in over 6 months. All I did was pull the main battery and then pulled the small CR 2016 button cell battery located inside the main battery compartment and re-inserted both batteries. The camera made a quiet click and then turned on with the main power switch and asked to reset the date and time. Works fine now. If this doesn't work just purchase a new button cell.

it seems that the camera section is haveing troube, may be in the lense movement or initilizing system. if the camera does not initilizes while swithcing on it turns itself off by giving low battery warning.