Windows 7 Cannot Connect to the Internet
No Internet access

The PC installed Windows 7 has not been able to connect to the internet suddenly.

When I started up the internet one day,it didn't work.
Because I had been able to the internet with no problem so far, this cause isn't for mis-configured.

A task tray shows "No Internet access" and "Undentified network".
Then, checking a "Network and Sharing Center".
The lan side is no problem but internet side is "No access" with x mark.

However other PC on the same network is able to connect to the internet.
Does windows7 has specific problem?
So, I've decided to research into it.

The Cause of Windows 7 Cannot Connect to the Internet

At first, I typing "ipconfig" in Command Prompt and confirm the present condition.

IPv4 Address. . . . . . . . . . . : 192.168.1.2
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 0.0.0.0
                                    192.168.1.1

This shows the result of "ipconfig".
Two "Default Gateway" are registed.

The correct IP address of gateway is "192.168.1.1" that is an IP address of LAN side of router. (In my case)
It doesn't need "0.0.0.0".
I think this is the reason that it doesn't connect trough the router.

I did network setting of Windows7 automatically, so I don't know why it became such settings.
Since I was being able to connect to the internet with no problem at first, the setting might have changed by some unknown cause.
This problem may have only Windows7 itself, but weird.

How to Connect to the Internet - Part 1

Anyway, I need to delete "0.0.0.0" from Default Gateway.
I have to add a route to became gateway is "192.168.1.1".

In particular, open command prompt with "Run as administrator" and inputting follow two lines.

  1. route delete 0.0.0.0
  2. route add 0.0.0.0 mask 0.0.0.0 192.168.1.1

Then, you should be connect to the internet.

Default Gateway became "192.168.1.1" only.
And once I was able to connect to the internet.

But it hasn't been connected again after reboot....
And "0.0.0.0" is again in Default Gateway.

How to Connect to the Internet - Part 2

I try to delete the driver from the "Network Adapter" in "Device Manager" so that reset from the driver.

The PC will ask you the confirmation, but continue the deletion.
Windows 7 has huge driver and backup driver installed in past.
So, almost all of driver should be installed again after reboot.

That's why I rebooted after delete the driver.

After all I was able to connect to the internet with no problem.
Windows 7 was restorationed by reinstalling of Network Adapter.

But I couldn't find the result.
It might happen again, because this is only returen to the previous circumstances.

Anyway if Winsows 7 cannot be connected to the internet by the Gateway problem, you do

  1. "Device Manager"
  2. Deleting the driver of "Network Adapter"
  3. Reboot

it manages to become well.

At least in my case, this problem haven't occured from then.