Uninstalling via Add/Remove Programs can cause problems...the correct way to uninstall is via Start > All Programs > Limewire > use the uninstall option there. Or, installing a new version will automatically remove an older version

Open Task Manager, check whether there's a LW process running. If there is, end the process. Now see whether Pro will install. If you still have problems, use your computer's search to look for all files & folders with limewire in the name & delete what you find. Then try reinstalling Pro.

Just make sure that you aren't saving your downloads to a folder with limewire in the name...or you could end up losing those when you delete files & folders after searching!