help please.. strange downloads and then file names in red!

[seagurl_2006]

i was downloading three songs so i left my computer running and closed out limewire... usually when i open it again the downloads are still there, but this time they were gone adn the song i had downloaded previously and cleared to my library was back again... i tried to download the same songs again but it said i already had them in the folder when my downloads are stored... i played them from there and now they are in my library but the names are in red text... i was wondering if this means something bad, like they are infected or something... they play perfect.. please help also i have had a copuple of downloads that get up to 100% and then wont finish... i would really appreiciate knowing what is going on and if those files in red are harmful to my computer... thank you!