How do I prevent my computer from automatically connecting to wireless networks and still be able to click...?

How do I prevent my computer from automatically connecting to wireless networks and still be able to click on a preferred network? So, I have internet from the cable company with a wireless router that my laptop picks up. Then, I also use earthlink so I can get internet in the city when I am away from my house. The problem is, when I come home instead of my computer always connecting to the wireless router from my cable company it connects to earthlink, or feather by earth link or wireless Philadelphia. Even if my computer says it is connected to Linksys, when I scroll over the little wireless icon in the bottom right it still says earthlink. I will click available wireless networks and linksys shows up, but after I connect, a second later it goes to earthlink. It is driving me crazy and I can't find a solution so my computer NEVER connects to those networks. I have tried removing them from my preferences, setting it so they do not automatically connect and all that basic stuff. HELP! I already tried all that basic stuff. It didn't work.