You changed preferences but did you delete the preferences folder? If not, have a go (points 2 & 3 in the thread below):
Fixes for LimeWire
Did you uninstall & reinstall Java as well as LW? Did you use the offline installers for both? Try removing your current Java version, then reinstall JRE using the offline installer (point 1 in the thread above).
Then reinstall LW using it's offline installer. If that's no good, also try changing compatibility to Win 2000 or NT (point 5 above).
If you're using any antispyware/security that might be seeing LW as a threat, make sure LW's on the list of exceptions/allowed apps.