@ kelleyelaine,
If it's still within the alloted time for free updates(6 months or 1 year). Click on this link and enter the e-mail address you used to purchase it with and it'll take you to your Pro d/load page.
Lime Wire » LimeWire PRO Lookup
If your page has expired, you'll have to repurchase it or d/load the Basic(free) version.
Lime Wire » Download LimeWire
You don't have to delete the old one, you can d/load it as many times as you want until your free updates expire.