Unidentified Network, Clean Win7 install, tried several NICs

I can't guarantee this fix will solve your problem, but I feel it's worth a try.

Click Start and type cmd in the Search field.

Right-click cmd and choose Run as Adminstrator to open the command prompt window.

Type these three commands and press Enter after each one in turn:

netsh int ip reset C:\netsh.log.txt

netsh wisock reset

exit

The command prompt window will close.

Restart your computer and check your network is clear.

I am wondering if the way that you are connecting is causing windows to disallow a "home" Network.

I cannot find definitive proof but I think that one of the requirements for a Home network is to be allocated an IP address in one of the private IP pools , (192.168.x.x or 10.x.x.x), rather than the direct ISP IPs you have.

there is no difference between the Home, Work or Public network type's ability to connect to the internet.

The difference in the network types is more to do with the Local access ....

• Home gives full local Peer to Peer access and homegroup,
• Work gives Full Peer to Peer and Client Server Access
• Public gives no local access (designed for Public locations such as coffee shops where you do not wish to allow others access to your files

.

As your PCs are in a public range it may be that the system is assuming that you are in a public environment.

You could try to check that DNS is operating - ping an external address, eg Microsoft or google and check that the reply shows an IP address. If you do not get an IP retuned, try using a public alternative DNS server (8.8.8.8 ), and see if this improves things

Strange, you seem to have everything covered ....

if the gateway on the non-working windows 7 machine is the same as a working win7 machine it should work.

The cable is OK as you can ping locally so that's not an issue (one of the main issues is mechanical connection in wired systems).

You have eliminated driver issues by the use of alternate NICs

You have reset the network stack

ISP can see your PC so external network is working.

Only thing I can think of is firewall .... glitch, are you on windows f/W or 3rd party f/W or Security Suite?

Can you ping external site by IP ? try google.com [74.125.230.112]

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BTW Homegroup is not a valid option in your network as HG is win7 only so would not allow access to MAC, you will need to use legacy Windows networking to allow access to MAC though HG will work between win7 systems assuming IPv6 is active and auto and the gateway supports IPv6

Ok one last thing to check on the software that I can think of ....

the windsock reset works on two registry entries that should have full permissions for administrators group.

SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\
SYSTEM\CurrentControlSet\Services\DHCP\Parameters\

check the permissions on these allow the administrators to change them (the reset must be done as administrator).

full MS KB is at .....

How to reset Internet Protocol (TCP/IP)

FYI

Yes that's the right locations - to check permissions right click the key name and you should see a permissions entry at bottom of list, select this and check that administrators and System have Read and full control.

Should not be an issue on a new system but you never know.

Last thing on a mechanical side is to disable the on-board NIC in Bios, boot into windows and remove the drivers (choose option to remove all files if presented), re-boot you can then try your USB NIC without any chance of interference from the on-board NIC or drivers if they are faulty, you may even find that a complete clean like this will fix the issue if you then re-enable the NIC in BIOS and allow a driver re-install, (let windows look for the driver first)