Try uninstalling Pro again (start > all programs > LimeWire > use the uninstall option). Now uninstall Java via Add/Remove programs.
Reinstall Java 1.6.0_03 first & make sure to use the
offline installer. Restart your computer.
Now reinstall Pro. Restart your computer.
When you deleted the preferences folder, was LW properly closed (check in Task Manager to see that no LW process is running)?
Is this your first try with LW, or have you had it running before without a problem?
Did you download Pro from the official site, or did you download it from another source?
You could also have a look at this thread (from a different forum) & see whether it helps...even though this person's LW was staying open for a minute or two.
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