Hello.
Since I upgraded to Windows 8.1 I've been having the same network issue: Internet connection seems to be lost for just a moment. I noticed that when I play an online game, sometimes, my actions aren't registered while I can see everything else going on fine. There are no ping spikes or lag spikes, it doesn't respond.
It also happens when I'm browsing a web. Sometimes the web is loading and then it will stay loading forever until I refresh it, then it'll load as fast as it does most of the time, as if the connection was lost while the page was loading.
However, it always shows that I have internet connection in the taskbar.
I'm using WiFi and this didn't happen when I was using Windows 7. I've installed all the windows updates and most of the drivers that I need. I haven't been able to find drivers for my network card and adapter since it is a quite old device so I had to use the drivers that come with windows.
Many thanks.