Did you downld the online or offline version of Java? "Offline" is recommended! Uninstall Java using add/remove control panel, reinstall using the offline version.

Delete all preferences of either .limewire or limewire in name using steps 2 & 3 of the link birdy gave you. ie: the 4.10 preferences are inside a hidden folder so you'll need to set your search to show hidden files & folders before doing the search. Application data is where new prefs folder will be found.

Then run this program (it's fast & is free) Crap Cleaner This will help to clean out your registry & old files that no longer are needed in the system's application support section.

Set up your firewall as described here to allow LW full access Connection problems? Check here first! (click on link) & make sure your modem/router's UPnP is enabled. See UPnP section in that link. Or else, manually port forward if necessary.

Then reinstall LW using the "Offline" LW version from here http://www.limewire.com/english/content/download.shtml