I just searched through the registry, and it seems that the only thing that gets written to the registry is the uninstall information. This means all you should have to do is delete the program directory and any shortcuts on the start menu or desktop. You will still have Limewire listed in the Add/Remove programs list, but if you try to remove it again it should say something like "This program is no longer installed on the machine. Would you like to remove it from the Add/Remove Programs List?" Then you just click on 'yes' and it should remove it. I haven't tried this, but, like I said, it should work. Worst case scenario, Limewire will be gone, but you'll still have it listed in the Add/Remove programs list.

Also, if it doesn't remove itself from Add/Remove programs, there are programs out there that will remove these entries for you.