googling suggests that your wireless hardware is Intel Wireless WiFi Link 5100AGN
you can confirn this by typing in a terminal:
if you cannot see that hardware in the list, tell us what you do have for a wireless controller.
if it is there, you need the iwlagn driver loaded.
back in your terminal, type
and search for iwlagn (you can narrow your search with '/sbin/lsmod |grep iwlagn')
if you do not find that module, try (you must be root for this)
again, and come back to us with your results