My Gateway MX8711 laptop got on my WIFI all right when installing Ubuntu 11.10, downloaded all the updates etc. Now after rebooting many times it will not pick up on the WIFI. I’m dual booting Ubuntu and Windows XP.
Try ifconfig or iwconfig to see if you have a wireless interface or not. May be you need to install an alternative broadcom driver. Try different broadcom option from Synaptic Package Manager with search keyword bcm4311. Or follow more instructions here.
How to solve: No wireless networks in Ubuntu