Share your experience!
So I set my alarm last night as normal, phone was on but not connected to wifi or internet. This morning my phone was dead. It won't turn on at all. When I hold the power button it buzzes once then nothing happens. I am sure it was over 50% battery last night so it shouldn't need charging. I have however tried charging it this morning. When connected to the charge the red LED light shows, this then changes to a green light. I then tried holding the power button and the volume up button at the same time but still it doesn't reboot. Any thoughts?
For me " buzzez " look like a water damage.
Did your phone had contact with water?
If you're sure it's not water damage and you see no condensation on your camera as well as the liquid sticker is white then I prefer doing a software repair using PC companion it will guide you through. Keep in mind that it will clear all your data like a factory reset so you should make a backup.
Keep us updated.
Its definitely not been in contact with water. How do I do a PC repair? thanks for you help 
By the way, if it is a water damage then don't contact your local Sony team like everyone posts. No they won't help you and staying sorry they mean " we are so happy that your phone is damaged because now you can pay for a repair and we make a profit :D" water damage ignores your warrenty and no one will talk about a free repair. You can tho request a vacuum test which will allow to see if device is waterproof with closed flaps. You can also put your device into a bag of rice (with all flaps opened) and close the bag tightly so no air will come in. Then after a week take it out, charge it for atleast 30 minutes and then try booting your phone
If PCC doesn't work then, contact your local Xperia Care
But its not been anywhere near water?
Thank you so much, i'll try this.
Sorry you wrote that it wasn't in water when I was writing on my tablet and didn't know you posted that.
Well
http://support.sonymobile.com/gb/tools/pc-companion/
Connect your device into computer and click update phone / tablet then on blue software repair and it will guide you through
I dont' think your issue its water related but you could request a vacuum test.