Sir can i ask with regards to my laptop inspiron

This is a common problem. The issue is almost certainly a faulty power board, a small PCB that accepts the power input and also holds two USB sockets – located on the top left side of the PC near the screen.
If your machine is in warranty the solution is a Dell repair/replacement.
If out of warranty then you will need to replace the component, or have someone do it for you.
The procedure involves buying a new power board, (Part number 48.4W006.021, available from Dell or more cheaply on Ebay at about £35), and replacing the old component. This is a task you should only undertake if you are comfortable with disassembling you laptop right down to removal of the system board. Instructions can be found in the Dell Service Manual at
http://support.euro.dell.com/support/edocs/systems/ins1526/en/SM/index.htm
This is not difficult if you are competent at this type of repair, but I would not recommend it for someone that has not taken a laptop apart before.

The power supply provides a voltage to the laptop to allow it to function
The laptop has its own built in charger circuit which uses that power to re-charge the battery while the machine is either on working or standby mode

If the battery is not being charged it is more than likely that the charging circuit has burnt out due to use or the old battery drawing too much current.

It is a repair shop job to check the circuit , sorry

A backstop would be to find someone with a like laptop and check your battery and lead against their machine