Delete download history/cookies?
 

when you do a search, files that have been downloaded have a special icon, how do you get rid of download history??

Do you mean the green tick icon? You can still downld the same file again, but you'll need to either rename it or choose a different location to downld it to. If LW doesn't prompt you 1st, then you can right-click the file in the downld window & choose your options.

You can also move the previously downlded file out of the saved folder & hit the Refresh button in the LW Library window so it re-accounts for what files are there.