Go to LW's menu bar, Tools>Options>Player & make sure LW's media player is disabled.

As for lockups, it could be due to a few things. Loss of communication with the connection device, Java not running well on your system, too many incompletes or shares, trying to do too many things at once with LW. Check step 1 here about rolling your java back to an earlier version Fixes for Limewire (click on blue link)