Please do try these steps that may help in turning on the wireless of your laptop.
- Go to Device Manager and expand Network Adapters.
- Right click on the wireless adapter then see if you'll get an Enable option and click on it.
- If these doesn't work, do try to uninstall/reinstall the wireless adapter.
- In Device Manager again, uninstall the wireless adapter.
- Next is to download and install the latest driver from Dell's Support site.
- Once installed, reboot your laptop then test if you'll be able to connect.