I could be the drivers, the router or the line.
If you need to restart your computer to make it work again, then it is probably a driver problem.
The audio problem are due to drivers too.
Look for support for your motherboard on the website of the brand. You can find which motherboard you have using CPU-Z. Download all up to date drivers that are for the operating system installed on the computer. Then, update the drivers. If this does not work, try uninstalling the drivers first before reinstalling the new ones.