I would like some sounds i downloaded to be used for start and shutdown music for my computer. My computer only takes wav files, but my music is in mp3 format. Is there some sort of program to change mp3's to wavs? Can someone help me?

http://www.google.ca/search?q=mp3+to+wav+converter&ie=UTF-8&oe=UTF-8&hl=en&meta=

Most programs you have to buy, although some offer free trial versions of the program. If you just want to convert a few files, those might work. Some music programs will also convert files.