Usually in such cases the mainboard failed and in most instances it is not worth to repair. You can either get a quick quote over the phone from agent for the mainboard and repair cost (usually more expensive) or go to laptop repair shops in Sim Lim for quotes. I had a friend last time replaced the mainboard for an Acer for few hundred $ and then it failed again some months later. There is suspicion shop may have used recycled parts for replacement but as the time lapsed for few months, he did not take it up further.