Well you can't really change your settings so that you'd only download from 4 hosts... strange. Try doing a completely new search for one of the files, use the All Types search. See how many you can download from this way. If you think your roomie might have messed with your options, just go right through tools > options & check everything. Or delete your preferences folder (it might be worth doing this anyway) when your downloads have finished... LW has to be completely closed. Instructions here
http://www.gnutellaforums.com/showth...threadid=36420

Just remember to make a note of any settings you're not sure of... you'll have to put them back in afterwards