Hi Shrabon Noman,
Thanks for the post. The error you’re receiving there is usually the result of the wireless card associated with the driver being used cannot being detected by the system.
I would suggest first making sure the hardware is listed in your device manager / the correct driver is being used and running Dell diagnostics on your system, linked below (To Open Device Manager by clicking the Start button, clicking Control Panel, clicking System and Security, and then, under System, clicking Device Manager. If you're prompted for an administrator password or confirmation, type the password or provide confirmation. The card installed should be listed under Wireless Devices. If devices are listed Unknown a great guide to help identify them can be found at makeuseof.com ).
If the card is not listed in your device manager, make sure it’s enabled via the hardware switch, if your system has one, and in your systems BIOS (The BIOS can be accessed by restarting your system and tapping F2 as soon as the Dell logo appears on screen. An option to enable / disable wireless devices would be in different locations within the BIOS depending on the model of system you have.
If not found in the BIOS make sure the cards physically well connected to your system, reseating it if possible to make sure the connection is good / swapping with a known good if available. For more comprehensive troubleshooting check out the guides below.
Run Dell online PC diagnostics
Wireless Networking for the Home for Windows 7