April 21, 2014 7:53 AM PDT
That's a big problem with lots of Free software these days. It is not actually viruses, but moire than likely ad ware and junk ware that is included with the program. Although most of the time not harmful, they are anying and you don't want them on your system... which is why AVG warns you of them.
Even the free downloads from sites like cnte.com - who used to be the most reliable source for free downloads - now has some type of adware in just about every program on their site.
I have personally stopped downloading any free software
for your mp3 to wav you can use iTunes to do it. Even if you don't have an iPod or iPhone you can still donload iTunes free from Apple.
Here are the instructions on converting a file...
http://support.apple.com/kb/ht1550 />