Missing file information. No idea why it doesn't show up

I noticed this one day when I was having my friend direct connect with me. For some reason, certain mp3 files that i am sharing dont show any artist title or album information. When i view them in Windows Media Player or iTunes, none of the songs are missing information. I have even gone into my folders and checked the Properties for certain individual files, and they all have all their information. But for some reason Limewire doesnt show information, aside from file name, for a couple hundred songs.

I know i can go in and put the file information in manually for each song, but it would take forever to fix all of the files, and i would have to find the files based on their file names, which range from title of the song and artist name to "Track 1". Putting this information in manually would just be completely unreasonable. I wouldnt care about this if it were not for the fact that my friend wants a lot of very specific songs from me, and this is really the only way to get the music to her.

I have found no real relationship between these songs. There are songs that i have just downloaded and havent had a chance to put information in for, but there are also songs that i got from a store bought cd years ago. Stranger still, some of the songs from a particular cd have all their information, while others dont. I cant figure out how to get Limewire to recognise the file information for these songs. Does any one know what is happening here, and/or how i might fix it?