Don't ever uninstall LW via Add/Remove Programs...it can cause problems! Use the LW uninstaller. Start > All Progs > LW & use the uninstaller there Also, installing another version of LW will automatically remove the old version.

First of all, update Java. Use the JRE offline installer & remove any old Java versions before installing the new one.
http://java.sun.com/javase/downloads/index.jsp

Next, delete LW's preferences folder when LW's properly closed. See point 3 below.
Fixes for LimeWire

Last of all, reinstall LW. You can download another Pro version whenever you like, using your personal download link. I'm a bit worried here, because you seem concerned about 'losing' the LW that you paid for. I'm hoping you haven't been scammed If you bought Pro from www.limewire.com then you'll have your personal download link, which you can use for 6 months. Basic LW is free & is available here
http://www.limewire.com/english/content/download.shtml
Always use the offline installer.