I am afraid there can be a plethora of possible problems here. But I recommend trying a few things before going to your dealer. First, try removing the battery and replacing it. Second, I recommend quality battery care. Read the owners manual for how to maintain your battery. It may be helpful to allow your battery to run all the way down. Then recharge it to full (but do not overcharge your batter). Then run it all the way down again. Third try replacing the battery or having a second one handy. Fourth, try removing any programs
you added and then reinstall them one at a time. Finally, IF ALL ELSE FAILS try a Master Reset. Remember that a master reset will delete everything you have added to your phone. To do this you need to go to Start, System
Tools, Master Reset. Good luck.