I decided to upgrade from Xubuntu 14.04 to Ubuntu Mate 16.04.1. Ever since the upgrade though, wifi connections suddenly drops and cannot reconnect.Even after I restart network manager through terminal, instead of the wifi icon i get the ethernet icon (weird huh?). I must restart the notebook in order for wifi to work normaly. Also, if I turn the wifi switch off and on, I get the wifi icon without showing any nearby networks, not even the network I'm connected. I believe it is random because I cannot identify a "trigger". I even tested standby mode and wifi works properly after resume.
I have an Intel 3945ABG wifi card.