Please check in safe mode with networking if you are able to go online.
To check in safe mode with networking follow the below steps:
Check if the computer is able to go online wirelessly in safe mode with networking.If you are able to go online using the wireless network in safe mode with networking reboot the computer normally and run MS fixit. Use the below link
Click the link above and select Run now.
If you are unable to go online in Safe mode with networking, try Power cycling the modem by removing the Ethernet cable from the computer. Reconnect the Ethernet cable and check the internet connection.
Check in Device Manager if there are any alerts on the Network Adapters.
Procedure to navigate to device manager:
If there are any alerts, install the Network card drivers from the Resource Dvd which was shipped along with the computer. If you do not have the disk use the link below to install the network card and wireless drivers update for the computer.
Please let me know if you have any other queries.
Thanks & Regards,Nikhil D#iworkfordellTo know more about Dell Product Support, Drivers & Downloads, Order & Dispatch status -> choose your region US Customers; India Customers. For Dell Support videos click Here.