There are heaps of fake & infected files being shared on the network! If the file size looks wrong (too small, or suss in any way)...leave the file alone! If an mp3 file's showing up with a file size in the hundreds of kilobytes (eg 119 KB) then it's way too small to be a real mp3 file & is probably an infected piece of junk.
If a file shows up with a file size in the thousands of kilobytes (eg 4370 KB) then it's looking like a real file.
Make sure that you're using a good AV program. Keep it updated & use it to scan all files that you download, before you open them