Dear Brother, when we select factory Reset tab and then press power button it simple reboot. When and how to press Vol Down Button. befor this if we press vol down button it scroll down the rom. Can you pls clarify little bit.
With the tablet switched off, press the Power button and the Down Volume button together. Thhe device should open to a menu of seven items and the last entry is Factory reset.
That is to make sure no-one can accidentally reset the device by accident and that is because it will delete all your personal files - music, photos, etc.
To get to that menu entry, you need to press the Volume Down button seven times until the Factory reset is highlighted. Press the Power button at that stage and the device will close down and when it comes on again, the process will start.
It's an Android phone, Google took over Android. You can't have an Android device without a G-mail address and account.
The reason we don't advise on passwords or swipes, etc. is because we can't be sure of the proof of ownership. You don't seem to know very much about this tablet and because of that, I'm stopping at this point.
Post back and tell me you've logged into a G-mail account using your PC or laptop and I'll continue to assist. There are ways and means available to Google to help you better than I can.