My iphone dropped dead all of a sudden. I can use it in the afternoon, however when I tried to charge it in the evening but not able to charge it. Please help me.

my iphone (3g) was given by my daughter who used it for 3 years. She did charged it everynight, however, when she gave me this iphone at Christmas, it was working properly and the batery last at least 5 to 6 hours when I used it continueslly. Last Monday, I used it as usal in the afternoon, work fine but when I tried to charge it in the evening, it will not able to be charged as usal. Is it possible to drop dead all of a sudden?

Lucy