That padlock notice you see at the top of your searches is to notify you of a particular search result that contains a virus...
It's a 75.7 KB .exe & shows up as "Urgent LW update - download & install now". If people download that thing they could end up infected. To try to prevent careless people from downloading a dangerous file, the warning banner was added to LW's interface.
The padlock symbol doesn't apply to music or video etc, only to LW updates...
Also if you downloaded Limewire from here, you will be OK. This is the official site.
Lime Wire » Official Website & Free Download, BitTorrent «.