The laptop I use runs MS-Windows 8.1, because a few software I have only run on that platform... It uses the WiFi to connect to my LAN. This is how I access the Internet, too.

Only once in a while (very often, if you ask me!), my WiFi would go out. This started to happen more or less when I switched from AT&T to Comcast. I did not really see what could possibly be different and all my other computers would continue to work just fine, including those used with WiFi too.

Many people say that your WiFi is bad or that you should change your WiFi Router... Or maybe when the laptop goes dormant your WiFi is turned off and when it comes back it fails... (only if the connection loss happens while you are working, that idea really does not sound correct, does it?! Not only that, if it worked for 2 years, why would it suddenly fail, frankly?!)

The fact is that the change from AT&T to Comcast came with a change of the DNS IP addresses. Since the WiFi uses a dynamically defined DNS (i.e. the DHCP server on my Linux server sends the DNS info to the WiFi connected computers) I really never thought that could be the problem. The fact is that Microsoft saves the DNS information in a cache and thus it remembered the AT&T IP addresses and somehow decided to use that once in a while.

What you have to do is reset that cache and then it won't fail like that anymore. This is done with that one command and a reboot:

netsh winsock reset

Running proceses will have the old cache still loaded in memory, hence the need for the reboot. The command will actually remind you of the fact.

Hmmm... After a few days, it does not seem to be enough. That being said, I went to Karate with my kid and used my HotSpot there. I know that gives me a different set of parameters as I connect through my carrier. So I may have to re-reset that cache each time I come back from there... Argh. More later.

Source: https://adamralph.com/2014/01/24/continuously-losing-internet-connectivity-in-windows-8-1/