Depends on how long ago you bought Pro. If it was less than 6 months ago, you can download again from your personal download page. If you didn't save the link, go here & enter the email address that you used to buy Pro
http://sales.limewire.com/support/pro_lookup.php

If you bought Pro more than 6 months ago, you'll have to pay again...Pro covers you for 6 months of free updates. It's always a good idea to save & back up your installers.