Hello, Everything was fine with my old LW and this for a few years and because of a spam email telling me to download the last version... I did and since then, it is impossible to connect. Nothing happens at all! I have a MacbookPro 10.5.8, 2 GHz Intel Core Duo, 1.5 Go 667 MHz DDR2 SDRAM, 512 Mo, I did open the firewall to all coming connections...
I read many things on the forum, but nothing seems to work... thank you for giving me new advices.I have a wifi connections, almost slow as I live in a small town in northern Argentina. What else could I tell you ?

Whilst LW is CLOSED, delete the LW preferences folder but first move out the Downloads.dat file to a different location. Then open LW up again, close it again. Then replace the new downloads.dat file with the old one. This will ensure your old downloads history is retained. Deleting LW Preferences folder in OSX.
LW 5 has the ability to find fresh people to connect with much better than LW 4 did. BTW if you use your OSX firewall, remove the old LW listing & add the newer LW to it.
OSX Firewall settings for Leopard

Dear Lord of the Rings ! thank you but inspite of your fast answer, I had already thrown all data/preferences about LW 4, so without keeping any of the old data I could not follow your advice totally, and now I just redownloaded the version 5.5.8, allowing it in the firevault... BUT still it doesn't work, so if you have any patience left could you just tell me what to do now I guess as a new user of LW and not any more as an old one.

Try setting up a Test account. Setting up a Test Account in OSX (click on link)
Try running LW from there. See if it connects. If it does, close it, move the Gnutella.net file from the LW preferences folder to the LW preferences folder on the main account.

May be I forgot to tell you something important, I downloaded the last version of LW because I received an email from : sm-music@m125.xoopa.net ... they send spam mails advising to update softwares like google earth, itunes, etc... among which LW, and instead of downloading from LW official website I did from theirs (I know it is a big mistake) may be or maybe not the reason why I cannot connect now ?
if not, your last email says to move gnutella.net from LW preferences but as I cannot open LW, I cannot find the preferences, so ?

No connection at all, the image just jumps once in the dock and that's it.
By the way my Java preferences does the same, is there a link btw the 2 ?
I just bought the CleanMyMac software in case it would help cleaning the limewire once in the trash to reinstall but... nothing new happens...
I also tried to download again the java for mac osX.5 but it says I already have it, what else can I try to make the LW works ?

I downloaded limewire 5.5.8, could not open. I desintalled it, redownloaded the old version 4.18.8 no more success... I downloaded frostwire 4.20.6, does not work... I do not understand why.
My info : macBookPro 10.5.8

Depends on your model of macbook as to whether you can use LW 5. Needs to be an intel 64-bit otherwise you are limited to using LW 4.

It's my guess your problem is with your original OSX installation and that Java is not working as it should. Over a year ago I had problems with LW 4.18 and 5 on one of my OSX installations but worked fine on same computer in a different OSX installation on a different drive (LW 4.16 worked fine.) Eventually LW 5 worked on the main OSX after 6 months however I'm not sure what the answer was such as a mac update or reinstalling java or reinstalling the osx from scratch (clean install).

Unfortunately on MacBook you only have one hard disk drive so you cannot experiment with a second OSX startup drive unless you partitioned your drive.