Sound problems...?

Hi guys, so recently I have begun building up my music collection again having lost it. Although I seem to have hit a problem as I can only play sound on my computer when I have played a game in fullscreen mode... It can get incredibly annoying as I don't really want to waste time starting up a game everytime I want to listen to music...

So can anyone suggest any help? I have been searching the web but as of yet have not found a solution. My OS is windows 7. Any other info will be provided if needed! Thanks! :D