Can't access to the internet. Only option is to use a system restore of the previous day.

1. wifi is wireless. you mean ethernet cable
2. run: cmd and ping command to 8.8.8.8
https://www.lifewire.com/ping-command-2618099
if you will see response then your problem is with DNS. -> google fix dns windows.
if not then your windows downloads some shit that breaks cables.
GET to your adapter manufacturer site and download drivers.

Being able to ping 8.8.8.8 doesn't mean it's a dns issue since seeing a response would work regardless if you had a dns server available or not.

Pinging a site by its actual IP address quite literally does not use a dns server.

In fact, I can set my dns to a random IP address and still ping 173.194.200.139 successfully, a ping of google.com of course fails.

DNS simply binds an IP address to an easier to remember name, like google.com versus 173.194.200.139

A more definitive way to solve this would be if you could ping 173.194.200.139 but you couldn't ping www.google.com

Whoa slow down guys. Yes you can ping 8.8.8.8 or an actual website like www.google.com. I guarantee the www.google.com won't work if he can't access a website via a browser. It's a quick check while troubleshooting but let's step back and look at the problem. And actually you want to run "ipconfig /all". This will return your IP and tell you if you are getting a good IP from your router such as 192.168.2.x. But lets look at the basics first.

Do you have another computer, tablet, or cell phone you can use to check the internet? Does it work? I assume it does since you set a restore of a previous date and it fixes the problem.

It could be some software that messed up your ethernet tcp/ip connection in windows. Anti Virus, Virtual Private Network, etc.... First thing you want to do is double check your cables and make sure they are connected all the way and the LED lights up on your router. Log into your router through the browser with 192.168.2.1 or whatever IP your router uses and double check that your router is connected to the internet. If you have a second computer/phone you can double check this way instead of logging into your router.

Next go to Network Settings in windows. Go to change adapter settings. You should see your ethernet adapter and it might have a red X through it indicating it is not connecting. Click on it and choose diagnose this connection. This often will have windows repair the tcp/ip connection and get your internet working again.

You basically want to get your connection working under change adapter settings in Network Settings. Assuming your router and cables are all good it's a problem in Windows. As a last resort you can uninstall and install the latest drivers for your ethernet on the motherboard and see if that helps. Download it from the motherboard manufacturers website. It could very well be that the ethernet is just malfunctioning but I doubt it since a restore solved the issue.

Try to troubleshoot and get back to us with more info.