I have the same problem.

Win XP Pro SP2
AMD 3800 X2
1.5GB PC3200
2X100GB Western Digital HD
NVidia 6600LE 256MB
DSL

I totally reformated my main drive, installed Java 1.5 (pain in the butt install which leads me to think this is all a Java issue), then Installed LW.

After 2 mins of Downloading ( after waiting for the download to start) it totally locks the system and you have to hard reboot.

No idea why.

Clues anyone??