Mark Twain wrote:
For the third time in as many days I
have only been able to connect by manually
pressing the power off button and then
comes back with abnormal shutdown and
then I select normal start-up and then
I get connected.

I shouldn't have to go this route to get
connected to the Internet and risk damaging
my computer.


This time, I'm leaving it on until we resolve
some things.

Robert


So when you restore from backup, initially
it is OK ?

And then it goes back to yellow-triangle/exclamation
mark on the network icon.

You have a few things which update themselves
automatically, such as your AV and Windows Update.
I don't know if there are any other things of
significance to the network connection or not
(stuff that might automatically update and
screw up the network connection).

I've had a problem like yours, and the fix was
to use NGEN and compile the .NET assemblies
(which somehow affected the Firewall). But I had
one other problem, that required reinstalling
the OS, because I'd given up on fixing it.

*******

As for the yellow triangle, Microsoft uses a specific
mechanism to test for network access.

http://superuser.com/questions/27792...-connection-re

( from http://superuser.com/questions/67760...nternet-access
which included a number of arbitrary fixes as well )

"The following list describes how NCSI might
communicate with a Web site to determine whether
a network has Internet connectivity:

1. A request for DNS name resolution of dns.msftncsi.com

[ In Command Prompt - nslookup dns.msftncsi.com ]
[ If it returns a w.x.y.z numeric IP, then DNS is working. ]

2. A HTTP request for

http://www.msftncsi.com/ncsi.txt

returning 200 OK and the text Microsoft NCSI

This can be disabled with a registry setting. If you set

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\
NlaSvc\Parameters\Internet\EnableActiveProbing

to 0, Windows will no longer probe for internet connectivity.
"

So that's how they figure out whether to show a yellow
triangle. If you had a proxy setup for Internet (sometimes
put there by adware, gumming up web connections), or a
badly configured Firewall (one based on .NET software,
where the ,NET software isn't loading properly), those
could be contributing factors.

But in general, I don't know of an all-inclusive troubleshooter.
Regular troubleshooters only issue the two magic commands
to reset the actual network stack. No troubleshooter verifies
the Firewall is OK. No troubleshooter warns you that your
browser is using a proxy setup. No troubleshooter can warn
you that your AV product is using a VPN (virtual private network),
or is otherwise interfering with network traffic. There are
enough external influences, to make this hard to troubleshoot.

And I tried testing this, which doesn't work. So that web site
does not accept numeric IPs.

http://206.248.168.139/ncsi.txt

Whereas this one works in the browser. So only symbolic
addresses and not numeric addresses work with the web
test site. So you cannot even use the site for effective
debugging purposes. You can try clicking this link, but if
it doesn't work, it's going to be harder to figure out why.

http://www.msftncsi.com/ncsi.txt

The reason that site behaves funny, is 500 million
computers check in at least once a day, so that web site
is actually a content distribution network (CDN). It's not
just a Plain Jane web server. But you can still browse
to that address and get the two-word response.

HTH,
Paul