text: how to connect with a wireless adapter - sometimes works - somtimes not? have a computer with a usb wireless adapter that find several potential sites with no security on them. sometimes i can connect to them (have mcafee personal firewall-build 7.1.113) and sometimes i cannot. wwhy? also, why do sites come and go on the site monitor(potential connections) in moments. connecting or not does not seem to matter whether i have firewall disabled or not?  thanks for your help! you're likely looking at your neighbors routers.  maybe they are using them, or not at different times.  where you are and what walls, and limitations of line of site are occurring when you connect will also effect the strength of signal which will result in more or less sites available.    worth noting it is illegal to use someone elses wifi connections that is not being intentionally provided to the public or being paid for by you.