ඔය drivers hide වෙලා ඇත්තේ. try this.
Go to Device Manager > select 'View' > select 'Show Hidden device'
Then Go to Network Adapter(in your case Dell wireless) > right-click > Update Driver > better go with 'Automatic Update' or you can try the other option >
Then select the "Action" tab on top & select the "Scan for hardware changes", If the 'Wifi' logo does not appear on the taskbar, please restart and check again.
Also, go to the Dell Support page, and get the 'Driver Update'
Often this happens due to issues with the driver updates. However, if the problem persists shudtown your machine and remove the battery, and try again after like 5 mins. This should fix your problem.