xperia shutting down at random

[#1]

i've had my xperia for almost two years and it's been shutting down at random lately.  about a month ago the phone started vibrating, black screen, wouldn't let me do anything.  i pulled the battery out and left it for a while.  it seemed ok when i restarted it but ever since it's shutting down at random.  doesn't seem to help to pull the battery out or the sim card.  also doesn't seem to matter if it's been freshly charged.  battery life seems to have no bearing on this issue.  does anyone have any suggestions on what the problem might be? 

[Samuel1]

I would suggest that you try to update/repair the software in your phone. You do this by using PC Companion (for PC, duh .. ) or Bridge for Mac. You find both of these softwares on the following link:

http://www.sonymobile.com/update

[ebuch23]

Unfortunately I have had exactly the same problem and if your phone is like mine, it will just get worse to the point that I couldn't get my phone on for 2 days! It's definitely not a battery problem as I tried my husband's one and bought a new one and it was just the same.

I had tried updating the software like suggested above and it didn't make a blind bit of difference. Luckily, my phone is still under warranty so I sent it back to SE and it came back saying a software update had been carried out (again). It worked brilliantly for 7 hours before it started re-booting constantly. So, I promptly sent it back the next day. I would get in touch with SE because their service so far has been really good (just a shame my phone still doesn't work!).

[yon]

it turns off seconds from the moment i turn it on.. I even also restored it into its factory settings but

still the phone turns off by itself.. Pc companion UPDATE doesnt work even it is stuckup into STEP 3, it never reached to step4(FINNISH  part)"