Hi MGJA,
I understand that sound has stopped working on your laptop and you can no longer watch you tube video's. I will try my best to help you with this issue. To better assist you, could you please give me some more information.
1. What is the Model Number of your laptop? LINK: How Do I Find My Model Number or Product Number?
2. What operating system are you running on the laptop?
Here is a document for No Sound from Speakers (Windows 8), that should resolve the sound issue for you.
I also suggest Using Automated Troubleshooting (Windows 8) to troubleshoot the internet issue.
I hope this information helps, please let me know how it goes.
Thank you,