Dell + Wireless Internet Connection?, Any computer geniuses around? Options

[misanthropist]

I have an old Dell C640, and just recently, I've tried to add a new Wireless Connection because it calls for encryption. I seemed to have missed a step in the process, but tried to attempt to press "okay" and see what happens.

Now, not only will it not connect to the new wireless network I was trying to add, it won't connect to wireless anywhere (when it could prior to the changes). I've tried going back and deleting what I did, but on my list of "Wireless Networks," absolutely nothing shows up, so I have nothing to delete. However, I am able to connect if I add the wireless network, say, at my friend's house to my computer. But I want it to automatically connect like it did before so I don't have to manually do it again? It's weird.

I have seriously tried from restarting to System Restore. Are there any computer experts out there that could possibly find some solutions to this problem? Thanks so much.