How to Remove Gmail Account from Sony Ericsson Xperia P

I have a problem with my old phone which is Sony Ericsson Xperia P. I do not know how to remove gmail account from gmail application which I downloaded for Andriod. I have added my Gmail account on my new mobile phone but I still rceive E Mails on my old phone. I hope some one here will help me to removemy Gmail account from my old phone.  

How to Solve Xperia P battery Life Problems

I purchased my New Sony Xperia P just before Xmas and I’m very happy with it. It has Android 4.0.4 out of the box firmware version is 6.1.b.0.544. At first was thinking why the Xperia P is draining battery so fast like after full charge “100%” it turns 99% for less than 2 min.  Few days back, I was playing Music using Walkman on my Xperia P at 11% (I’m washing dishes) then after washing my Xperia has 6% left well I Surf for a few minutes until it reaches 2% while was getting the charger it suddenly went to 1% and 0% and turned off automatically (the first time I drain it to 0%) 

My question is that is someone else also having same problems or had same problems and how do I fix battery drainage problem on my Xperia. Thank you in advance  

How to solve MESSAGING Problems with Sonny Ericsson Satio

My friend is having problems sending any messages with his satio, he can make and receive calls and he is  also able to receive any incoming texts. However when attempting to send a message to anyone the message goes to outbox and continues to postpone itself but never sends. Can anyone help please?