Hi @ABSOLUTSAM, 

Welcome to the Dell Community!

Could you please check if wifi is ON on the system. E5540 has a wireless switch on the left side of the system, toggle the switch and check if the wireless is ON. 

What operating system are you using? What happens when you install the wireless driver? Please share your findings and private message us the service tag for further assistance. 

-Regards,

Tabassum M 

Hi Tabassum,

Thank you for your quick contribution. Please find my response below:

1. I have toggled  on/off the wifi switch at the left side of the laptop as suggested and this didn't resolve the issue.

2. I am using Windows 10 Operating System.

3. As per what happens when installed, it would respond that "windows has determined that the best drivers for this device is already installed", however, after disconnecting the ethernet connection, the wifi icon still didn't show.

4. I am sorry I do not understand how to private message the service tag.

Kind regards.

Hi ABSOLUTSAM, 

Thank you for sharing your findings. Please refer https://dell.to/2ZSGESb follow steps shared by Priyam Tripathi on the forum. Once you perform the steps wireless icon should be back. Then connect to wifi and let us know if it works fine.

Incase you see the wireless icon and continue to face issues, please run network troubleshooter to check if that helps you resolve the issue.

1. Select the Start  button > Settings > Network & Internet > Status.
   Run the Network troubleshooter
2. Under Change your network settings, select Network troubleshooter. Follow onscreen instructions.

To private message, click the user name Dellcares and on the right side of the page you have an option that says

My approach, as posted here, may also help you.

https://www.dell.com/community/Latitude/cut-wifi-on-and-then-it-goes-off/m-p/7453625#M18326