Sorry to tell you, but there are no Pro refunds (click on link): Refund Policy - Lime Wire

What's happening when you try to reinstall Pro? Are you seeing any errors when you try to install?

Can you download the Pro installer, or are you getting an error when you try to download?

If you're unable to download the installer at all - where did you buy Pro from, who did you pay (check your credit card statement or any email receipt you might have recieved) & and how much did you pay for Pro?

I'm guessing that you're having trouble downloading a new Pro... the only official site for download of basic (free) LW or Pro is Official LimeWire Website & Free Download of P2P, Gnutella & Torrent Client - Lime Wire

The official site offers...
* Pro ($21.95 - includes free updates & email support for 6 months)

* Extended Pro ($34.95 - includes free updates & email support for 12 months)

* A one-off download of Pro ($13.95 - one download only, no updates, no email support). This option seems to only appear sometimes on the official site.

Which one of those did you buy?