I remove msn on every system I have .
never used it. never needed it. So I can't say anything about it.
Limewire on the other hand
I have used and I still use it.
Todate I have only had 2 bad files downloaded off it.
both had the wrong extention on the files.
MP3 showed on the list.
They were Not mp3's
I have NO idea what they were.
I don't waste the time on them
I just wipe them off my system ( wipe=wipefile)
I scan everything I download from limewire before using it.