Windows Movie Maker Stops All Sound

I was working in Movie Maker and I was putting in a picture and a mp3 made the picture match up to the mucis and when I was trying to watch it before I saved it there was no sound coming out, I check my speakers, audio card and no resolve everything else was working fine. Then I could not get sound from any other places like Youtube, Mixx ect. The only way to get the sound back on was for me to restart my computer. Then a few hours later, Windows Essentials did an update and it still does not work.