Share your experience!
On a brand new Xperia V, when opening up an application, it randomly goes back to the home screen, and it continues clicking as if the touchscreen was still sending signals. Then, if I try to touch it, it does not respond. I have uploaded a video so you can see what I mean: http://www.youtube.com/watch?v=LFPQlECzOBo -totally random stuff and unuseable.
This is a brand-new, just unwrapped phone with no extra applications installed. Tried repairing using sony bridge but it did not work. Do I have any other option apart from returning it?
It depends on where your warranty is,if you have sony warranty,you could go to sony,if not,go where you bought the phone.
So I bought Sony product and I dont have warranty for it because of buying it in normal shop? Crazy...
It depends on the shop,of where the shop gave your warranty.The shop may have given you warranty to one of their services,not sony.
I have the exact problem and I just bought it 3 days ago. The Sony Center does not open until the end of the holidays. The new phone is useless until then. 
I made another video with DevMode on and tracking screen inputs:
http://www.youtube.com/watch?v=R0DthcH0Yoc
It seems like its a hardware issue and the digitizer is indeed acting up so its definitely a case of bad QC on Sony's part.
I got this from an online store so will be shipping it back and insist on a replacement.
My problem is solved. I just sent it back to the place where i bought it and i got brand-new Xperia:) It tooks about a week, but new phone is in my hands right now.
I am happy for you.
Wish I could have changed my xperia phone like you did. It's gonna be a while till I hear from the service center about the status of my phone. So depressing! 