Did you put your board away in working condition, pick it up a few days later and it won't turn on?
This can happen for a number of reasons:
Your battery is dead- Charge it!
You board has a hardware failure, this could be due to water damage, excessive battery drain or a fault which we cover under warranty.
You should first try charging the board for a few hours to try to revive it.
If that does not work, you should open the enclosure and unplug the battery from the electronics as a safety measure. Follow this guide for help
You should then complete a Service Request for next steps.