Hi, I suspect something else is going on.
Maybe a hardware failure or bios issue.
When you can not connect copy and paste this command in the terminal (ctrl+alt+t) please:
It will download a script and create a text file in your home folder with wireless information so we can see the condition of your wireless at this time and the Mac address, WPA key and WEP key are removed for your security, then reply back and attach the netinfo.txt file.
wget -N -t 5 -T 10 http://dl.dropbox.com/u/57264241/wireless_script && chmod +x wireless_script && ./wireless_script