Ok make sure both have different SSIDs (which you have) put them on different channels, and dont broadcast the ssid on the encrypted one. what is probably going on is the computer is seeing both and wants to connect to both so it gets confused. make it so it cant see both or so that it can more easily tell the difference (before encryption even occurs) and it will be less confused. Putting them on different channels will probably help a bit but not broadcasting one of the SSIDs will help a lot Im thinking.