Ok are you posting from the computer in question?
If so we know you are not using a 3g network.
I assume you are connecting to a wireless connection with a ssid.
If so you are connecting to some sort of router/ap in your house.
If you open a command prompt and type ipconfig it will list your default gateway. This is where you need to change your wep key by logging into said device with the proper username and password.
Actual model names really helps as saying cisco wireless adapter does not help. It is like if you ask me what kind of car I have and I tell you a red one instead of a 1997 Toyota 4Runner sr5.