Go to your Pro personal download page (I presume you bookmarked the page, wisest thing to do) & download the installer again if you deleted the previous Pro installer. If not then go to your email & get the link from there. Otherwise get the link from your CC receipt. Otherwise get it from the
LW Support page.
The problem will either be preferences, too many incomplete files, too many shares, Java installation issue, LW compatibility mode or admin setting.
http://www.gnutellaforums.com/333278-post2.html except use your Pro installer.