Only a little help.
Sorry but if you need lots of help, I have to write you need to find it locally.
Here's a small item that I hope will help.
1. Did you install Dell's QuickSet? Without that some Dells will not enable the WiFi.
2. Is the date and time right?
3. Is the antivirus expired? (some lock out the internet when expired or when you uninstall them.)
Good luck with this.