Ubuntu 14.04 wifi problem

http://forum.ubuntu.cz/index.php?topic=64896.msg462647#msg462647
http://ubuntuforums.org/showthread.php?t=1970820
http://askubuntu.com/questions/298097/which-iwlwifi-firmware-for-intel-wifi-link-5100
http://askubuntu.com/questions/261988/no-longer-able-to-use-wifi-adapter-intel-wifi-link-5100-ubuntu-12-04
http://askubuntu.com/questions/454325/cannot-connect-to-wifi-at-home-after-upgrade-to-ubuntu-14-04
http://wireless.kernel.org/en/users/Drivers/iwlwifi#Download

Ubuntu 14.04 wifi problem