Are these torrent or gnutella network files? Torrent files may stall because nobody else online has more % of the file than you.
I've had two torrent files sitting at between 30-60% downloaded since start of year, despite 40+ others online with same file, they all have same % as me & are also waiting for someone to come online with the entire 100% of the file. Unfortunately with public torrents there are too many hit & runs, they get what they want then don't share back.

Gnutella files may stall because LW can't find more users with same file with available upload slots. Another reason they may stall is because they are fake files or similar such as the user having upload slots set to zero.
Best answer for gnutella network files is to search the file again as you did originally then 5-10 mins later right-click the search result tab & choose Find More Results.

Another alternative if above does not work is find an alternative file in search results that is the same topic file but shared by someone else.