Some store brand computers especially from small computer shops do not include a front/drive cage case fan and rear exhaust case fan in their computers.
Such fanless computers will build up heat within the computer’s case leading to a computer shutdown when the cpu is too hot. A hard disk failure will also occur if the hard disk temperature exceeds 55-60 Celsius. Above 50 Celsius, decreases reliability.
To prevent this, please check that your computer has 2 case fans and they are working. You will need to clean them occasionally, when having a computer, having good desk mats should be a must.
Also, an external hard disk is not meant to be used actively. For example, installing a program on it then running that software throughout the day. An external hard disk does not have a fan attached or airflow from a case fan thus may overheat and fail.
This problem is more acute in warm Malaysia unless your room is air conditioned or well ventilated.