Every program stores their settings in a file in the preferences folder. For Mac OSX you can find them here: /Users/your_username/Library/Preferences/LimeWire

But only do it whilst LW is closed! Before you do it make a note of all your LW settings. After you delete the preferences you will need to reset these option settings.

Firewalls: Did you configure them to allow LW through? Is Port 6346 open? Check your firewall instructions for allowing certain apps access through. Net games & video conferencing would also need to be given permission to pass.

Virex! I thought it was only an anti-virus application!

Are you sure your OSX firewall is not active? If yes you'd need to do the same thing. I can provide instructions for OSX.