As you travel around, you more than likely connect to many open wireless networks. When you tell WIndows to Connect Automatically (see image below) you save that network’s profile on your client.
If you are in an environment where you have set many of the networks to connect automatically that are all within range of each other, you may find yourself connected to the wrong network. Here is how you set your order preference of wireless networks.
From the returned search items, click Network and Sharing Center.
Click Manage Wireless Networks.
Select the network that you want to be preferred and then click Move Up.
Move it above the other networks that you want to give it preference to. That way you will connect to that network when multiple other networks are in range.