MacBook air not turning on but charging

My Macbook Air is 3 years old and it stopped working overnight. I could see the battery is charging, but nothing shows up. Its not turning on. I went to apple service centre for repair, they are not able to find the issue and identified small corrossions on logic board and they are suspecting that might be the issue. I havent spilled any liquid on the machine, they said it might have happened due to moisture. They quoted a very high price for replacement, so I took my mac back. I have attached their diagnostics report. They showed me corrossion picture of logicboard, but didnt share it with me. I would like to know whether this could be a hardware issue or software issue. Can a corrupted software can cause the macbook not to turn on or should the issue be isolated to hardware. If it is a software issue, how can I check it as the macbook is not turning on.