Thank you for your post.
You may need to check if your wireless adapter shows up in device manager at all. Click on the start orb then right-click on computer then on Properties, then on the top-right click on device manager. In device manager double-click first on “network adapters” see if the Intel wireless adapter is listed, if not then check if you have an entry under “Other Devices” listing an Ethernet controller.
If you do see an “Ethernet controller” listed in ‘Other Devices’ then you are just missing the drivers, check on the Dell* website for the appropriate ones. If you do not see the adapter in device manager at all then it may be a hardware failure, in which case you would contact Dell for a replacement.
If you find out which wireless adapter and Operating System you have we could post the generic drivers in case you have trouble getting the ones from Dell.