You can stop sharing files completely by going LW>Tools>Options>Uploads>Slots and reducing the number of upload slots to " 0 ".
However, if all people were about to do this, what files would you download then????
I reckon sharing at least some files. You can control which files you want to share by going LW>Tools>Options>Sharing and adding/removing those files you want or do not want to share. If you need to reduce the number of people trying to download from you, you can do so as described above typing the number of download slots you're willing to offer.
