Why is my phone not opening just vibrating?

[bappi islam]

My phone is Galaxy note 3 (SM-N900V). My phone's battery is OK. After giving it the official ROM lollipop it was OK for few days. But after a few days it just vibrate but do not open. Several times i reset or wipe it. but it fails to run. What should i do now?

 

[Rukbat]

The official ROM for THAT model Note 3, or just some Note 3 ROM that's for a different model? Flashing the wrong ROM can cause that. So can a phone that's gotten wet inside (even if it's just condensation).