i would:
- try to format the new card in the pc to make sure you don't have the same problem
- then put card in camera & format
- test if camera now works
- if it works, download new firmware & upgrade
- note: even IF the camera stil gives the "format message" you can upgrade.
the camera will definitely work, but it's just harder to find the images in case you need them, because the dates are all mixed/wrong
the "format card" message does NOT mean that the camera no longer works.
the camera just looks at the (wrong) date and thinks it's been a long time since you last formatted.
as described in the thread, you can change the internal battery yourself. But it requires some guts, and you should be prepared to take the risk (to brick the camera)
if you don't feel confident, then just take it to an electronics repairman & have them do it.
However, make sure you familiarise yourself on how to open the camera & where the battery is located, so you can guide them on the process
PS: Misschien kan je hem naar Philips brengen, die zitten toch niet ver weg