Unable to connect Internet - DNS error - Windows 7


I have a new (3 months old) Dell XPS Desktop Computer with Windows 7 (64-bit), the Motorola SBG6580 Wireless Modem/Gateway, and Comcast is my ISP.

My computer is connected to the modem with an Ethernet cord. I don't have anything unusual about the setup. I just plugged in my PC and it worked.

For the past three months everything was working fine. Then all of a sudden, as of last Friday I can no longer access the internet.

The Connection icon on the bottom right is showing that I'm plugged in, and every few minutes a yellow exclamation mark pops over it. Some websites open very, very slowly, some don't open at all, and other just give a straight up error that I'm not connected. It's weird - I can connect for the first few seconds when I re-start the computer, and the speed is extremely fast, and then all of a sudden I can't connect.

When I right-clicked on the connection icon to troubleshoots sometimes it says "The DNS isn't responding" and other times it can't detect any problem (but I still can't access any websites).

Now, I also have two game consoles connected with Ethernet cords to the modem and they're working fine - I can get online, play games, stream movies etc. My wife and I can also connect our iPhones over Wi-Fi, and I can also connect my laptop running Vista over Wi-Fi.

The problem is just the Windows 7 PC.

I've already googled the problem and tried every solution offered - I flushed and renewed the DNS using the ipconfig commands, I set the DNS manually but nothing seems to work!

Could this be a virus of some sort? I have McAfee running, and I performed a scan but it doesn't detect anything. My gut feeling is that there's a virus that's changing the DNS.

Any suggestion on how I can confirm, or what other steps I can take?



Question Info

Last updated November 18, 2018 Views 133,175 Applies to:
Perform steps mentioned below and check if the issue persists.
a:  Click on Start and then Control Panel.
b: Go to Networking and sharing center and then click on Change adapter settings.
c: Right click on Local Area Connection and choose properties.
d:  Highlight Internet Protocol Version 6 and click on Properties.
e: Choose Obtain DNS servers address automatically and press Ok.
f: Choose Obtain IP address automatically.
g:  Repeat the steps for Internet Protocol version 4 as well.
Hope that helps.

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