Mobile phone Samsung D900 discharges

Question

Mobile phone Samsung D900 discharges battery in approx 4 hours - only started happening recently (may be to do with bluetooth?). Have bought new battery and charger (as advised by contract supplier) but same problem exists. Wanted to reset phone to original settings but default password will not work (do not know if the password has been changed).How can I reset phone to see if this helps or can anyone give any possible solutions?Joe Mc T