The Interesting Case OF The Lost WiFi

Question

1.    Context
2.    Description of the problem
2.1. History of the problem
2.2. Partial solution
3.    System specs
4.    Apologies
1. Context
I am currently halfwaythrough a 3 months trip in Guatemala, in which I decided to bring my 13’’ mbp,a great decision. Just like anywhere in the world, many cafés, hostels andrestaurants in Guatemala offer free wifi, which helps me stay connected with myfamily and friends. I started having problems connecting through wifi a fewweeks ago, and it just kept on going worse from then. Since I didn’t have my OSX intallation disk with me (I know realise that I should have made animage...), I upgraded to Lion as soon as I managed to connect to a fast enoughconnection, but the problem remained. Although my applecare coverage is stillon, Guatemala barely has two apple service centers, both located in thecapital, a long and costly bus ride back and forth that I would like to avoid.
2. Description of theproblem
When trying to connect toa specific network, I get a no connectionnotification, or sometimes a full five bars signal, but with no internet.
3. History of the problem
The first problems I hadwere with the similar networks. One of the big providers here is namedTURBONETT, and many networks seem to be named with that exact name nothingadded. My computer would try connecting those networks it thought it knew thepassword, and usually prompt me with a noconnection message. I had a hard time trying to stop it connecting to those known networks, as even forgettingTURBONETT woudn’t work. I then started having that problem with any network I remembered : It would automaticallylog on, with either a full signal, but no internet or a no connection logo. It usually was caused by the password havingchanged (the cafés often change password to prevent neighbours to vampirizeit), but since it would automatically log on, even if forgotten, it would be impossible to enter the password (evenmanually). That problem would eventually spread to networks I try joining forthe first time, making it hardly possible to connect to internet at all.
4. Partial solution
I managed to log on to afew networks using the assistantfunction from the network preferences. Sadly, it only worked 2 or 3 times.
5. System specs
Macbook Pro
13-inch, Mid 2010
Processor  2.4 GHz Intel Core 2 Duo
Memory  4 GB 1067 MHz DDR3
Graphics  NVIDIA GeForce 320M 256 MB
Software  Mac OS X Lion 10.7.2 (Although the problemfirst occured on up-to-date Snow Leopard)
6. Apologies
I would first like toapologise if I, by error, started my thread in the wrong section or missed asimilar thread that could have answered my question. I did do a lot ofpreliminar research before writing those lines (as it is waaaaaay easier thanto as kit yourself), but feel free to redirect me to anything I might havemissed.
I would also like toapologise to those who might find many flaws in my way to describe or tryresolving the problem. Although I think I know my way around OS X, I still haveonly scrached the surface, and this is the very reason why I ask for your helphere.

Answer 1

Bump
This recently happened to me as well, actually it's happened for awhile, and only recently have begun to try to find the answers. Did you ever find out what happened?
Also seems like this post: http://discussions.apple.com/message.jspa?messageID=11367180
But that has no answers posted either. Perhaps a reformat and stick with 10.6.2, which is what I think the last version the "Shared Devices" automatically showed without deliberately mounting a network drive.
My situation is pretty much the same, "Shared Devices" do not automatically show up on the left sidebar. If I know the IP address or netbios name, I can mount network hard drives: Command + K and smb://ipaddress
My Computers, I have an iBook G4, which used to automatically pop up; a Windows7 computer that used to automatically show; and an Ubuntu 10.04 computer that would show up as well for screen sharing and smb.
Possible culprits include: netbios/smb problems, mDNSresponder/Bonjour problems, other networking config. No settings permutations have fixed the problem.