The manual says: if the camera does not turn on after you have inserted battery, lease check whether the battery are inserted with correct polarity (+/-)
Never use unnecessary force to put the battery in the chamber.
If you are not sure the battery is still ok, try two other batteries type AA. The camera will work with non rechargeable alkaline batteries and will work with rechargeable Ni-MH batteries.
When the battery chamber is open, please check if the metal connection point are not corroded and clean.
You still can find the manual online and the thing I describe here is on page 8