So im trying to fix a computer from a customer. The problem is that when the customer change the voltage of the powers supply from 115 to 230, the computer suddenly shutdown. and when they turn it on again. they notice a strange yellow light (Maybe a spark in the power supply) and its not turning on. NO POWER. FAN IS OFF. ITS BASICALLY DEAD. . So what i did is remove the current power supply and change it to a working one. It did turn on but theres no display in the monitor and every 10-15minutes, it shutdown. i also change the battery(THE CIRCLE BATTERY) of the MOBO and still the same. its literally not booting. what do you think is the problem?