I can see the Wireless Networks but I Can't Connect any of them!

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http://askubuntu.com – I used to be able to connect to Free Wireless networks and to my Own wireless network, but when I tried to connect to a wired network I did One Thing: Restarted the network-manager in the terminal. Since then I can't connect the any wireless network and never got to connect/test my wired one (I couldn't get it to work, thats why I did that). Could someone help me with this problem, because I can't seem to find any post with this same problem or a good answer. I tried to edit my Wireless connection and delet it in order to try to connect again but, like I said, the problem is I can't conne (HowTos)