The Roaming folder should not be deleted however. Just the LimeWire folder inside. The Roaming folder is a part of Vista's set up AFAIK.
If you found LW partial programs inside the LW folder, that's not unusual. LW shares updates through other people's computers. Thus when people are installing or updating LW, parts of the installation data is actually shared across the network, not all of it comes from the site that has the installation files.