Share your experience!
my t2 ultra was working fantastik until yesterday 12.00 pm and all of sudden in morning it is not starting up.
i dont know how to dill with it .
while i connect it with charger it shows led but doesnt starting up.
Hello @Arjunpatel and welcome to the forum!
I'm really sorry to hear that. 
There are a few things you can try in order to get your phone up and running again.
First of all, try pressing and holding the power and volume up buttons at the same time for about 10 seconds or until the phone vibrates or press and hold the OFF-button next to your SIM-card until the phone vibrates. Use a paperclip, pen or something else Then connect a charger again. I would also recommend that you remove your SIM- and/or SD-card followed by booting your phone.
It might take about 30 minutes for the device to indicate that it is charging if it is completely discharged, during this period the display may remain black. Try charging your device for about 4 hours as it can take a while for a completely depleted battery to fully charge.
If possible, use a Sony original charger and USB-cable specifically intended for your device. Other chargers may be too weak or too strong as they may have a different electric current rating (mA).
Should the above not help I would recommend that you try performing a software repair using Xperia Companion? Note that this will reset the phone in the process. Performing a backup will unfortunately be difficult if you are unable to boot your phone. If you are able to boot your phone you can create a backup using the Backup feature found on the main menu in Xperia Companion.
Keep me posted! 
thanks xperia staff
i worked on it and find some google tips also. but it wont help to start my phone back. i tried to reboot threw reboot botton. fully charge but led is not turning green. so finally i went to xperia care and they took only 5 min and told me that if bettry isuee than it will take 3000 to 3500 INR and if failure of motherboard than it is upto 7000-8000 INR.
i dont know what to do because it is too much to spend 8000 INR on two year phone.
i'll appreciate your better response again.
I see, I'm afraid that if my previous suggestions didn't help with getting your phone up and running again this might be related to hardware rather than software.
I would recommend that you have your phone sent to an authorized service centre to be examined. For information regarding local warranty and service procedures I would suggest that you contact your Local support as they will have more information on that subject. As these procedures differ between markets I'm afraid I cannot assist you with sending in your device.
I hope you get your phone repaired as fast as possible, let me know how it goes!