Q: iphone 5s screen suddenly turned blue and turned off.

Howdy there snthileepan,

It soinds like you are not able to turn your phone back on after it turned off unexpectedly on you. I recommend the troubleshooting in the following article to help you determine if that can be resolved, named:

If your iPhone, iPad, or iPod touch doesn't respond or doesn't turn on

If you see a black screen

You might need to charge your device before it can turn on. Plug in your device and let it charge for at least 10 minutes (20 minutes for iPad), then try turning it on. 

You should see a battery icon while your device is charging. If you continue to see a black screen, reset your device. 

If your device doesn't respond when you press buttons

Your device might not return to the Home screen when you press the Home button, wake from sleep when you press the Sleep/Wake button, slide to unlock or power off, or it might appear frozen. Try these steps:

1. Restart your device.
2. If it still doesn't respond, or if it doesn't turn back on, reset your device.

If your device gets stuck during startup

When starting up, you might see the Apple logo or a red or blue screen for a long time, or your device might restart again. Try these steps:

1. Make sure that you have iTunes 12 or later on your computer.
2. Put your device in recovery mode.
3. When you get the option to restore or update, select Update. This will reinstall iOS without erasing your data.

 

Get more help

If you still need help after trying the steps above, contact Apple Support. 

Thank you for using Apple Support Communities.

All the very best,

Sterling