Talverson, It's VERY RISKY turning off your Firewall. I also have NIS2007 and have never had a problem. Just make sure you are giving Limewire Full Access. Also check your Windows Firewall. Turn it off if it's on. Running more than 1 Firewall will cause more problems as they will conflict with each other.
This a Large sub forum but there are so many variables, would probably be best to browse through to get some ideas.
Connection Problems
Also might try these fixes.
If LW Will Not Connect
Hope this helps.
