If you're using windows XP, disable your XP firewall. XP & Norton will conflict if run together. Also for Norton, you can see * Configuring Norton Internet Security

Make sure your modem/router has UPnP enabled (if it doesn't support UPnP then manual port forwarding is probably the answer), instructions for this here Connection problems? Check here first! (click on link)

If you're using anti-spyware programs, be wary of the ones you use. Some don't work properly & think LW has spyware when it doesn't. We recommend these two: 1. ad-ware (FREE), & also 2. Spybot - Search & Destroy (FREE)