Pentax S40 Does Not Remember Settings

Hi all

I've been using my S40 with Ni-MH batteries for almost 2 years.

For the past half a year or so, I notice that the system time always goes backwards for half a day and some settings such as exposure does not get saved each time I turn on and off the camera. Other settings like background and quick zoom works OK, but some settings just keep getting forgotten when I turn the camera back on.

I tried resetting to defaults, changing batteries, but no help. Any ideas? Thanks.