Convert FLAC files to MP3 and AAC (and question about my mouse)

I'm looking for a free program that can take FLAC files and convert them to MP3 or AAC. I have a program that had a limited time on its advanced features. It won't let me convert these files now. It is promoting the paid version. I'm looking for a free program that will convert FLAC files that has no restrictions like this.

Also, my mouse has a problem. Sometimes, when I left click, it registers two clicks, one after the other, and really fast. It is annoying sometimes. What is my best solution? Buy a new mouse? I have had this one since 2007 or 2008.