You may remember I had a post talking about Comcast upgrading to docsis-3.1 and getting new equipment to handle it. I have the new equipment which is backwards compatable so it works on 3.0 or 3.1. Everything was working fine and then Comcast made the switch on Feb.1,2018. Now I keep losing the routers internet connection to the computer. The router is close to the computer so it is hardwired.
I cant figure out why.It is the TP-Link AC1750 router. Any ideas?

First stop is to contact Comcast and let them figure it out.

Actually it sounds like the router's connection to the Internet that's to blame. The internal connection between the router and your computer should be the same as before -- and that was working. You can always ping the router from your computer to test that connection.

Like Draclvr said, it's probably Comcast that has to fix it. Any problems in the cabling between your router and the Internet are their responsibility.

If you haven't done so already, turn off the router for a few minutes and then turn it back on.

I don't know if you have fiber, but if there are any stretches of cable between you and Comcast that use older copper cable, they may not be capable of supporting a higher Internet speed and may have to be replaced.

1). It is not their equipment its mine. Also my cabling.
2). I have turned it off and on. That's how I get it going again. Doesn't last though.
3). It is fiber from street to house. Inside house is coax.

You'll have to contact Comcast about it then.
The thing will disconnect if your signal is too weak, so Comcast will have to send someone out to test your signal.

I changed the Ethernet cables from modem to router and from router to computer and have not had a drop out for over 24 hours. The cables I changed were brand new and came with the new modem and new router. I realize new stuff can be bad but one certainly doesn't expect that. Assuming the problem is fixed it had to be those cables or something Comcast fixed on their end that I don't know about. Do you agree?

I'd give it a few more days! You could always reconnect the "new" cables and see if it starts dropping out again. If it does, you can assume it was the cables... if it doesn't, then who knows. Maybe a connection wasn't just right or maybe Comcast did something.

This is why I HATE working on networking stuff!

Yes. I think you nailed it.
Though I think it's more likely Comcast fixed things on their end. Whenever they roll out a big change, like moving to DOCSIS 3.1, there are likely to be some problems, some adjustments to make. Hopefully they've straightened it out by now.

Is there a difference between the actual plug on a cat-7 cable as compared to a cat-6 cable? Im wondering if the new cables were cat-7 and were slightly different and my computer being an older Win-7 didn't like it?

Interesting question... I had no idea, so I've been doing some reading. I don't think your operating system had anything to do with it, but I'm wondering about your network card or chip. Can it handle the speeds... I recently put a stand alone network card in my computer and it was rated for 1900Mbps WiFi speeds (1300Mbps on 5GHz band or 600Mpbs on 2.4GHz band). I wonder what your internal card is rated for?

The pictures of the cable ends that I'm seeing for cat7 cables all show metal end connectors, and I'm reading that cat7 cables have to be properly grounded.
https://www.google.com/search?q=cat7+eth...OO_Dx5gKamIiYAQ

So I don't think you'd confuse them with cat6 cables, which have normal plastic end connectors.

You might need a different ethernet card to use cat7 cable.

That's what I was thinking too, Jenny... his network card may not be capable of handling this upgrade. Wish I knew more about this stuff!

No No its working since I changed the cables so my equipment is all ok, I just thought there might be a difference in the cat-7 cables. I noticed the new cables seemed to wobble a little bit in the jacks and thought there might be a slight difference.

As far as a physical difference in the cables and how they fit into the jacks, I couldn't find anything that they were different.