Sound and Video stops suddently.

So, this error is ocurring a long time ago. I'm only posting this now because it's getting worst.
Out of nowere, i can't play a video or a music. But if it's already playing, for exemple, a video it continues playing it.
This usually takes ~5 min but sometimes it takes 10 min or so.
Also, i play League of legends and it stops responding for that time.
It is really annoying, hope someone can help me.
Sorry for my english! :D