Can't access to a free wifi network

[Adamantios]

I got a MB and I am not very into Mac software, most of the time I am trying to get access to free wifi networks because I travel very often to specific countries, so my MB can remember all those networks and save them in its keychain, but when I try to access to a free wifi network that I have used before, my MB scans the area, I see the network and click on it nothing happens, so when I try to set up the airport access, it says that the network has a password, but actually it doesn't, and I can see it because everybody can access but me. After being a long time trying to access, finally a miracle happens I can get access to the internet, but sometimes i just can't even if I try for a long time. Some of those networks has a password and I write the right one but again nothing happens, it so frustrating. Please I need your help. Thank you so much.