Please do try these troubleshooting steps that may help.
- Start by pressing fn+F11 to enable the Wifi and Bluetooth capability of your laptop.
- If it doesn't work uninstall/reinstall the wifi adapter and bluetooth driver.
- Open Device Manager and uninstall both Wifi and Bluetooth driver.
- Once uninstalled, reboot your laptop and it should reinstall the driver automatically upon reboot.
- After the reboot do test if your Wifi and Bluetooth will work.
- If it doesn't work do run System Restore and restore it to an earlier date or time before the problem even happened.
- Here's how: http/windows.microsoft.com/en-PH/windows-8/restore-refresh-reset-pc
- Lastly, if all these will not work run a Factory reset to reinstall Windows.
- Here's how: http/www.dell.com/support/article/us/en/04/SLN117599