My speakers are acting up, please help!

Hello,

My speakers have been acting funky since a couple days ago where they'll play Microsoft Media Player but won't play from youtube or any other website from the internet. In short, they do not recieve sound from the internet. I've been trying to watch my anime and play my music for the couple days now but they still won't work, the troubleshooter so no clue how to fix it and I've gone to many help sites and recieved none at all.

Help me please!