I believed what Microsoft advised: "Your network card may not be ready for Windows 8.1 and to cosult with the maker of the motherboard" It turns out that Asus is not providing anymore updates for the built in network device. So, I bought a new network
card, which is 100% windows 8.1 compatible.
Yahoo!!! the problem DID NOT GO AWAY!
But I found a work around which, kind of works for a while longer.
This is what I did: when the internet stopped working, I pressed the "Windows-Search key" (Windows key + Q). Then I typed and I searched for "Diagnostic Policy Service" (without the quotes). Somehow, windows search enabled the network and it started
working again.
The other way, I got it working again, is by search for a new windows update. Either way, enables your network again.
Is it a Microsoft problem? hmmmm, I would say it is!. What do you think?