Sun 1.4.2:
http://java.sun.com/j2se/1.4.2/download.html (Choose the JRE) You can find the version of Java LW is using by going to the Help>About LW ... menu.
(Sorry about your sig. I put it back, I didn't read the whole thread.)
So you tried deleting your prefs folder? Do you have your video card set up specially for games (specific settings)? (Some people have also found with their video card that if they reset it to default it seems to fix some problems.)
How many versions of LW & Java have you had in the past? Do they still exist on your computer?
Try reducing the no. of shared folders (OR reduce the no. & size of files within the folders might be better & safer) as an experiment. Also go to your incomplete folder & list it in order of size. Delete all those that are 0 KB. Then after opening LW, arrange downlds by Progress (click on top of column heading to do this), & select all those at 0% holding down the SHIFT key to select all of those at 0% only & press the Stop button to remove them from the list. This should take some weight off LW when it's starting up.