If you are having problems getting Windows 7 to save your Wifi password, hopefully this will help. In my case there seemed to be too many folders in the interfaces folder.
This is the post where I found my answer
It happened exactly the same for me too. Except I AM running WPA2 security!
The WLAN password is encrypted and stored in an XML file in c:\Program Data\Microsoft\Wlansvc\Profiles\Interfaces\..GUID\.
However, the xml file was being deleted so the settings not kept. I made the file RO after logging in and connecting and now all is fixed.
Goodness knows why this is happening though.
(You need admin rights to be able to change the file attributes).
The key here is the Interfaces folder. In my case I had a plethora of folders in there, that I saw no need for. Five folder for two routers?
So I deleted the oldest folders, disconnected from the network, reconnected, it asked for the password again, I entered it and hey presto it created an XML file in the newest folder.
It may also help switching on the “Automatically Connect” option, connect to the network, let it save the password and then switch off the auto connect option if you want to.