Canon Powershot A620 - replacing date/time battery

[Kamal Hans]

I've had this great camera since 2006 & it has served me very well.
Of late, whenever I turn the camera on, I get a prompt for setting the date/time; evidently, the rechargeable Lithium battery has weakened considerably.
I have searched all over the net to find out where this battery is located & how to replace it but have been unsuccessful.
I would be grateful if a kind soul could plz help me.
TIA