Most likely because you have left your laptop on charge constantly without it needing charge causing the battery within the laptop to become instable. (basically replace the battery)
yes my laptop is charging
What do you mean pretend laptop?
Yes as over-charging the laptop reduces it's battery life.
did you mean to ask what to do if your laptop battery is not charging? if that is the case http://laptop-battery-not-charging.com/ might be able to help you.
No, because there is nothing to charge.
The way to stop your laptop from charging is to unplug the charger from the computer. When the battery starts to get low on power plug it back in.
It Means Charging
as long as you have your laptop plugged in, you can use it.
No.
After charging laptop it will 3 to 4 hours backup
No. Your laptop is all classed as low voltage equipment.
You cannot tell. You would need to turn it on.