No sound at all and all sound-using programs crashes

Hi all

I'm using Windows 8.1 on my MBP with OS X Mavericks on it. A few hours ago, I was listing to music on YouTube and I wanted to sit somewhere else so I closed the lid of my MBP and reopened it at the other place. After reopening I noticed that my sound wasn't working, also when playing YouTube videos they stopped at the 7s mark.

Any other program that is using sound (Skype, Spotify, VLC Player,...) crashes when I try to use a sound-needing function.

I hope someone has already had this issue so it can be fixed quickly.

Thanks in advance!

Arne