Internet going down while downloading or watching video.

Hello. So I've just installed my Windows 8.1 and ran into a little problem that keeps me away from using W8. So, as I try to watch any video on Youtube (or anywhere else) or downloading few programs after 2-5 minutes of video or download time the internet disappears. I've tried disabling Firewall, play with other settings but nothing helps at all. After the disappearence of the internet I have to restart my PC (because without restart Troubleshoot seems to do nothing) and run Troubleshoot. It says that my Wi-fi is shut down but I skip this one, because my internet is on cable. So then I get another "Problem found" and it says "The Ethernet adapter is disabled".

I hope that someone has accured this situation and knows answer to this problem. Thanks.

Check for Viruses and use the

Speedtest.net by Ookla - The Global Broadband Speed Test

tool to check your Network. Also run a "troubleshoot" on your network from within windows 8.

When this has happened to me in the past, it was caused by VIRUSES or Malware. Or Rootkits, so as well as your AV, download TDSSKILLER and Malwarebytes Anti Rootkit and fun the full tests.

Well, it's a fresh copy of Windows 8. So, don't think that viruses has anything to do with this.
Here's the result. Speedtest.net by Ookla - My Results
As I said troubleshoot does nothing.

Check your drivers for the network card. Sounds like they may need updating. When the troubleshooter says the ethernet card is disbaled, check the Network Connectons window to see if its disabled there aswell.