Check that you don't have a Windstream firewall - see this post: http://www.gnutellaforums.com/218807-post7.html

If that's not the problem, make sure that your Windows firewall's allowing LW: User Cant Connect - LimeWire

Otherwise, try the fixes in this thread. Start off by changing port numbers: If LW Will Not Connect

If none of those fixes help, could you try to find out the model of your modem/router (box that plugs into your computer & lets you connect to the net)? If no info's showing on top of the device, turn it upside down & the info might be underneath. If you have a wireless connection, the router might be in another room