I’ve replaced the battery, upon which it started up, then (presumably) ran out of that battery charge and now won’t restart. I’ve also changed the charger. Charger shows green light. I’ve done all the Reset options, too.
Apple has some suggestions here:
If your Mac doesn't turn on - Apple Support
If none of that helps, then most likely either the battery you used is defective or something got damaged during the replacement process. Apple probably won't touch the MBA now, but you can visit an Apple Store or authorized Apple service center and ask.
Regards.
MacBook Air says it’s charged (green light for hours) but won’t start
