No one is replying to your question. I don't think I'll be too much help. All I can tell you that I have never had this, or even heard of, this problem. I would make sure your mp3 software is not corrupted. You could try reinstalling it if you suspect it is.

Your other suggested possibilty of the virus scenarion seems highly unlikely. I don't know of anyone (in their right mind anyways) who would make a virus that attacks mp3 files. Normally, they go for .exe, .com, .bat files, and similar files. But it does sound more plausible that a virus could be attacking other software, such as mp3 players, on your system, thus not playing your sound files correctly. It is easy to contract viruses off of LimeWire if you're not careful, so make sure your antivirus definitions are up-to-date. If you don't have any anti-virus software package, I would recommend you obtain one.