When I opened a particular app my screen got blue and then I pressed off the power button, since then I am not able to open my

[nituparna]

When I opened a particular app my screen got blue, then I pressed the power off button, and then after that I was not able to open my phone, it remains on black screen, it doesn't take charge even, what can I do??

 

[webworkings]

I would suggest that you have the phone looked at, either by the manufacturer (if it is under warranty) or a local tech. An app should not prevent it from powering it on.