Open your terminal, type:
sudo gedit /etc/network/interfaces
And remove those lines that come AFTER iface lo inet loopback:
auto eth0 iface eth0 inet dhcp
/etc/network/interfacesfile should said:
auto lo iface lo inet loopback
Make sure to save the file before you close anything. Reboot the system.
The problem was each time you start your computer, Network Manager try to auto connect using the wired connection as your primary connection instead of the wireless connection.
This solution work if you are getting that error message about:
"waiting up to 60 seconds more for network configuration..."