Rooting an Android phone means gaining a super user authority of your phone. After rooting your phone you can install any unauthorized applications,install update for operating system and many more you can do for customizing your phone.
If someone is using Linux then its like sudo and Rooting=JailBreak in I-Phone.
So Today I will be using Free window Tool to root your phone.
1. Download and install Kingo Android Root on your windows PC or laptop.
2. Now enable USB debugging mode on your Android phone.
For Android 4.0 or 4.1 :
Go to Settings-->Developer options and tick the "USB Debugging" option.