Alice - it's doubtful that you'll be able to repair your TV set. The loud bang you heard suggests a component exploding - very probably a capacitor in a power supply circuit but that's just a guess. Someone confident with electronics might be able to make a home repair - it may be possible to identify what caused the bang just by looking.
I think your realistic options are to buy a new set or/and take the broken set to a repair workshop - the cost of repair may be close to the price of a cheap set.
