Ech. If your BIOS has been set to allow wireless and your firewall is allowing wireless connections then
the integrated network card has departed. Screw Intel anyway.
If that's the case, you have two options.
First, you can buy a new internal network card. Chances are you can get one for $50 USD. To install it, you'd need to pry open the case, remove the shit card and install the new one- you'd need to know if the socket inside is PCI, PCIe, or AGP. The new cards have the type printed on the box.
Laptops are not my forte, so I cant tell you exactly how that would be done- I imagine it's the same as a desktop, but you violate Dell's shitty warranty and it's fiddly in there.
OR you could buy a USB network adapter. For the same 50 - 100 USD you can simply plug a device into your USB port and install some drivers and viola, you're sailing the digital seas once again. No shit, that's all there is to it.
This assumes you're not using all of your USB ports for something else.
These devices come in both wireless and ethernet cable versions- that's right, a usb to ethernet cable adapter. I have faith in cables myself, but it's your choice.
As far as types, your only real concern is protocols and that should be handled by the architecture. If in doubt, look for the product's protocol listing. If you see 802.11 then you're good; otherwise you're probably looking at a bluetooth protocol and I'm afraid I'm of no use there.
Heavily modified to sound like English.