Originally Posted by doodownunda
Ok after reading all this I see you have tried all logical fix's.
I agree with doc that you should try a new battery as they are cheap on e-bay and worth a try.
If it still doesn't work then you may have hardware issue or something, like a broken rubber/spring under your back key.
So you may have to pull it apart and try to repair it, so it makes or stop's making contact in your situation.
You can find how to dismantle your phone if need be here on xda or google.
If your thinking of replacing it you may as well try as you may surprise youself
hope you get it fixed.
Haha, I love all you people as to how sincerely you help people and listen to them in the call of their distress. Anyways, if we are discussing this : here's what I want to propose : 1) Trying a new battery : I connected the devise to a external wall DC Supply (battery removed) and connected the opposite ends to the plates where battery connects in the back cover. Tried switching on the Xperia from there. Got the same response. So nothing new Nada. So a new battery is out of picture. Though thanks for putting it on the table, but I guess it will hardly solve the issue as I already tested it with the External Wall DC supply. Double checked the battery with the Voltmeter to see the charge, its charged capacity is over 80 %. So, cant be a faulty battery as well.
2) Thanks for letting me know about the guides regarding how to dismantle the phone. I would politely disagree. Reason : Well nothing that I am sure about, It can be a issue (hardware defect of spring being broken) I find it less probably. Coz the night b4 it was working fine and I just put it on table, woke up and it was Boom ! So, until unless, someone might have caused any harm to the device I guess its safe for me to rule that option out as well.
3) So, narrowing it down to what I might think the problem be : Since it does not boot normally and boots irregularly to Flash Mode, my best bet against the whole situation is that I need to fix the boot sector of Xperia. If i can some how set the boot sector right, I guess the boot can be again done and restored perfectly. A friend of mine suggested RF Kit, JTag for Xperia X10 boot repair. Thanks, let me know what you think. !