Lately, I've noticed that some of my mp3 files are disappearing a day or two after I download them. I can't find them in the folder, and even when I do a search on my computer it doesn't turn up. However, when I try to re-download it, it says that file already exists and asks if I want to over-write the file. But again, either computer search or manual search, I can't find the file. What's going on?