FIX Windows 7 "Unidentified Network - No internet access" error

I have been experiencing a very strange error in my home Windows 7 installation since the very first day I installed it. I have a Dell Vostro desktop PC with an ethernet Intel(R) 82562V-2 10/100 NIC, and I noticed that after some boot ups the Network Connection showed up with an warning icon (a small yellow triangle with an exclamation on it). Indeed this indicated there was a problem. The exact warning message was "Unidentified Network - No internet access". It seemed the problem was that the NIC could not determine which network I was using, although I already have a "Home" network properly configured that worked fine before the last boot, and as it could not determine which network I was using it simply didn't connect to it, so I had no LAN nor Internet connection.  Unplugging and plugging sometimes worked, other times it didn't and I had to reboot the machine, sometimes only to find that it had the problem again.

I googled for the problem and found many, many people experiencing this same problem with Windows 7. There were also many solutions proposed here and there, in forums and in the actual Microsoft Technet site. I tried everything, from uninstalling the driver to modifying the route tables (a "phantom" 0.0.0.0 route was accused of being the culprit) to change settings in the registry... nothing worked definitely, all of the mentioned solutions only worked temporarily or the didn't even worked. I was very surprised to see that this problem, even as it seemed to be affecting a lot of people, was not workarounded by Microsoft after many years of Windows 7 out there.

After many "tries and errors" I came to the conclusion that the best way for me to get rid of the error everytime it appeared was to go to "Network And Sharing Center", then click on "Adapter Settings", and then Disable the network connection and reenable it after some seconds. Sometimes this did the trick at first, sometimes I had to repeat this process 3-4 times before the network connection showed as "Connected".

One day a couple of months ago I had, as usual, the error on boot up. I started the mentioned method but after 9 or 10 cycles of disabling-enabling the connection it didn't connect. Then then they were 15 or 20 cycles... nothing. I decided it was too much and I have to get rid once and for all of that error (if I could get connection at last!). 

I always suspected, don't ask me why, that this problem could have some relation to the speed negotiation of the NIC. I decided to give a try to change the adapter's speed parameter and set it to manual, so the operating system didn't have to "guess" the speed of the adapter everytime the system booted up. So I forced the adapter to work in "Full Duplex at 100 Mbps".

It is two months now since I changed this setting and the problem has not come back a single day (it was showing up 2-3 times a week before), so I think the problem is solved at last, and I recommend you do the same if you are facing this same problem.

This solution, obviously, works fot a wired network connection. I don´t know if there is a similar workaround for wi-fi connections since I have not experienced this problem with wi-fi connectios.

So. to change the NIC adapter speed parameter follow this instructions:

- Go to "Control Panel"

- Go to "Network And Sharing Center"

- Go to "Adapter Settings"

- Right-click on the connection with the problem

- Click on "Properties"

That brings up the local area connection settings, as you can see in this image:

- Click on "Configure..."

- Click on "Advanced Options" tab

- In "Properties" section look for "Negotiation speed" and click on it

- In the right side, "Value" field, chose "Full Duplex at 100 Mbps" (or, in case you are connected to an old 10 Mbs switch, select "Full Duplex at 10 Mbps")

- Accept and close all the windows and restart

I hope this solution also works for you. Please leave me a comment if it did!!