Is it set to automagically connect? or listed as the preferred connection?

During some play time yesterday, I roamed the neighborhood and found bunches of networks I could see and a couple I was able to actually connect to. During this play time, I changed a setting to no longer automagically connect to my own network (a Belkin Pre-n router, secured, MAC addressing, et cetera). When I finished playing and wanted to reconnect to my own network, I had to turn the network SSID on and re-enter the pre-share key in order to gain access to my network. Note, the network was still secure, but I do not care to broadcast the SSID.

I would look at the security settings, password/pre-shared keys, et cetera. If you are getting a signal, most of the work is done.