If LW pops up all the time, it's usually because of a worm. Try the fix here, it's worked for a lot of people.
http://www.gnutellaforums.com/showpo...&postcount=141

Files turning into zip files is also usually due to a worm (different worm to the one that causes the popping up thing). People have found that AVG free AV has been able to fix this problem for them. Download AVG free. Update it & scan your computer. See if it finds a worm (Delf.ATB)
http://free.grisoft.com/doc/2/lng/us/tpl/v5