Could be the adapter, jack or mainboard.  It'll be covered under warranty - call Dell.  Alternatively, if you're in the US and bought direct from Dell, you can return the system for replacement within 21 days of shipment.

Hi  Arsalan Jamil,

Check if the adapter is detected in BIOS.

How to check the status of AC Adapter in BIOS:

• Restart / Power on your computer
• At the first text on the screen or when the Dell™ logo appears, tap until the message Entering Setup appears.
• AC Adapter will be listed in the Main tab.

Also, refer the following links which has steps to fix the issue:

http://dell.to/14Av7rH

http://dell.to/16NwLn9

Connect a known good adapter to see if it works.

Awaiting your response!

Thanks Rajesh for the reply.

I follow the steps you mentioned, below is the result.

- Ac Adapter type  --- <65W>   in Main tab.

- Adapter Warnings ---   in Advance tab.

Also, Inspiron 5521 is not listed in table for adapters (the links you provided).

Is it low power adapter? Should I replace and use high power adapter?

Please suggest.

set the "adapter warnings" to "enabled".

what "adapter warnings" does? what If I set to 'enabled' ?

Can anyone reply me please?

Hi Arsalan Jamil,

Try uninstallimng and reinstalling the Quickset application:

• Click Start.
• In search type “Programs and Features”. Press enter
• Uninstall Dell Quickset.
• Restart the computer.

Add or remove program in Windows 8:

http://dell.to/1dMXsyI

Install:

http://dell.to/15wQgna

Also, update BIOS on the computer:

http://dell.to/1a4P5cJ

• During BIOS update verify that the computer is connected to an AC Adapter.
• Disconnect any third party peripherals connected to the computer before performing BIOS update. 
• Do not turn off the computer during the BIOS update.
• Do not restart the computer during the BIOS update.
• Ensure battery charge is more than 30% during BIOS update.

Note: Plug your computer to a good, working UPS before you update the BIOS. If you experience a loss of AC power or a significant voltage sag/spike during the BIOS flash, you will either have to buy a new BIOS chip or buy a new motherboard.

Let me know the status.

Hi Rajesh, Thanks for the reply.

following your instruction, I uninstalled and reinstalled Quickset application and updated BIOS on my system but Issue is still the same i.e. still getting quickset popup.

Hi Arsalan Jamil,

Check with a known good adapter.

If the computer has active warranty I shall go ahead and arrange for a service to replace the part.

If the issue persists, Kindly private message me the service tag of the computer. To private message the service tag click my User name and click Send a Private Message.

Check warranty status: http://dell.to/10pMa86

Awaiting your response!