Lou88888888,

Which version of Java did you try...the latest update, or the older archived version? Did you remove all existing Java versions before installing another one?

After you deleted the preferences folder & started LW, did you have to go through the LW setup wizard again?
Did you also look for a preferences folder in the old location of C:\Documents and Settings\your username\.limewire (not a hidden folder)?

Did you make sure that LW was properly closed when you deleted the preferences folder & also when you replaced the gnutella.net file? Did you also try uninstalling LW, reinstalling & then relpacing the gnutella.net file (as raffles did in the thread I linked to)?
If you reinstall LW, make sure to use the offline installer. When you click to download LW, cancel the dialog box which pops up & use the option to download the offline installer.
To uninstall LW, go start > all programs > limewire > uninstall. Don't uninstall via add/remove programs.

If basic LW isn't working, don't buy Pro!!