Download the "Offline" version of Java. It's always the safest. Did you check your 3D settings for the NVIDIA card? Java 1.5 is better for LW & should only use 1.4.2 if you're having problems with graphics card.

Make sure your firewalls are all set up to allow LW full access. If you see a brick wall in front of the blue world icon at the bottom of LW's interface? If yes, that means you have firewall problems. You have your XP firewall, but your modem/router may also have an internal NAT firewall. If yes you need to check whether it has UPnP support or not. See tips on setting these up here Connection problems? Check here first! (click on link)

BTW with SP2 you may or may not be interested in one or both of these patches: MS & 3rd party patches