An electronic apparatus includes a motherboard, a random access memory, a motherboard battery and a processing unit. The random access memory is disposed on the motherboard. The motherboard battery is disposed on the motherboard and electrically coupled to the random access memory to supply electrical power to the random access memory. The processing unit is disposed on the motherboard and electrically coupled to the random access memory. The processing unit is configured to write a test value into an idle address register of the random access memory and further to check whether the idle address register maintains the test value. When the idle address register maintains the test value, the processing unit determines that the motherboard battery functions normally. When the idle address register reverts to an initial value, the processing unit determines that the motherboard battery malfunctions.