I sold a computer about 9 months ago. It had an Intel motherboard, and worked well until the customer reported that the internet suddenly stopped working.

After some initial telephone diagnostics, I decided I needed to visit and see what was happening.

At this stage, I’m guessing that the ethernet drivers might need re installing

I first noticed that the network adapter was disabled by Window 7

So I enabled it, but then, whenever I tried to see some adapter information (eg IP address), the window would just show the “waiting” cursor. It was effectively locked up (yet the rest of windows was working fine).

I noticed that the antivirus detected and removed a virus on the same day this problem occurred… a coincidence?

Device manager said the device was operating normally.

After a few minutes, one of the frozen windows displayed the error:

Com surrogate is not responding

Hmmm, It was all a bit too strange, so I took the computer back to the office, and had a more careful look.

I did a RAM test (RAM is ok)

I tried safe mode (with networking), but still no network.

Eventually decided to plug in a USB WiFi adapter, to see if I could get to the internet a different way… and this worked.

The next step (now that I have internet access) is to do a full malwarebytes scan… but no malware was found.

Looking in the event log, I find:

session “microsoft security client oobe” stopped due to the following error: 0xC000000D

I also find a few errors about reading hosts file

So also create a blank hosts file, and that fixes the errors, but not the internet access

I remove and reinstall the ethernet drivers (broadcom gigabit netlink controller), but that doesn’t fix it.

I found a reference to removing the file:

C:/program data/microsoft/microsoft security essentials/support/MSSEOOBE.etl

But that didn’t help either

OK, how about uninstall Microsoft Security Essentials?

Still no go.

In the end, I decide it must be a fried ethernet adapter chip.

So I disable the onboard ethernet adapter, plug in a new PCI ethernet adapter, and that works perfectly.

Isn’t it strange how we can be fooled into believing that there’s no hardware problem, just because windows says so…