Vista Network Issue - "Unidentified Network" & Loss of Internet Connectivity

UPDATE: See Items in Red under "Next things to try".

Ohhh Windows Vista baby, you were doing so well!

Right, I logged on to my PC yesterday morning to find I had no Internet connectivity. My first port-of-call? The "Network and Sharing Centre" of course! The nice little graphic on the screen there then proceeded to tell me I was on an "Unidentified Network". "Hmmm, that's odd" I thought.

So, I think "lets fix this damn thing". I run the network diagnosis this to fix it, and I am presented with a dialog telling me that I need to reset my router - I don't really believe this, but what the hell, I reset it anyway. Still no Internet.

Weird, so I then fire up the command prompt "cmd.exe" (with admin privileges) and run "ipconfig /all" to have a look at what's going on. I then see I have been assigned an APIPA address. I know this normally happens when there is a problem communicating with the DHCP server on the router. Now, this never fails on my router, so I figured I would fire up the craptop (my crappy laptop) to see if it works. I was able to connect without any issues both wired (using the same wire as on my desktop to check the cable) and wirelessly, as well as refresh my IP address via DHCP with the laptop. Right, this has just got really interesting, because my craptop is running Windows XP.

So theoretically its not an ISP, Router or cable issue. So it has to be something on my Vista desktop. I then think, "ok, maybe Vista is not liking the DHCP configuration, so I disable the DHCP Client (using "services mmc snap-in") and configure a static IP address (using the same network info from the laptop - other than the actual IP of course). I reboot and confirm the IP address information has been set, via "ipconfig /all" - but, you guessed it, still no Internet.

So, I'm starting to get more confused now. Static IP's nearly almost always work, they can just be a pain in the ass to maintain.

I start thinking maybe Vista Service Pack 1 (SP1) is the issue. I know I had it as an update around the time it all went bad, but I know the Internet has been working fine with it, but I don't care, its not working now, and that's the only change that my system has experienced recently. So, I fired up System Restore (in the "Backup and Restore" Centre), and restored to the point before SP1 was installed. Annnd... No joy (suprise).

I'm now getting increasingly angry and frustrated. I then think that maybe System Restore couldn't replace/fix some of the settings/drivers/lunar alignment/whatever. So I wipe the entire PC and reinstall Vista from scratch. After the setup completes, I know I am back to square one as I have lost everything, but guess what! STILL NO GOD DAMN NETWORK CONNECTIVITY! ARRGGHHHH!

I have tried a few other things following a google of the issue (which showed I am certainly not alone in this)..

So, to summarise:

Things I have tried (to no avail) - mostly in order:

• Running the "Diagnose" in Network and Sharing Centre.
• Rebooting the computer, TV, toaster,  light switches, kettle, flooring, walls, house, UK, Europe, Earth and Solar System.
• Assigning a static IP.
• DHCP release/renew.
• System restore to pre-SP1.
• Disabling IPv6.
• Clearing the WINSOCK/Ipv4/Ipv6 stacks.
• Checking the Router's DHCP configuration by using another (XP) computer on the same network (which worked fine).
• Checking the cabling by using the same cable in the above wired test.
• Applying the registry fix suggested in the Microsoft Knowledgebase (KB) article 928233.
• Disabling the second Network Interface Controller (NIC).
• Putting the computer to sleep and waking it up again.
• Uninstalling the Network Controllers via device manager and rebooting and letting Vista set them up again.
• Updating the Network Drivers.
• Leaving and rejoining the workgroup.
• Reformat the machine (GOD DAMMIT!).
• All of the above post-format.
• Praying and asking for an act of God.

My thoughts based on above:

• It can't be the router or cable, since both are still working fine with the laptop.
• It must be something to do with the desktop.
• I cant see how its a configuration issue since I have completely reformatted the machine.
• I doubt it's the NIC's because its a week-and-a-half-old computer.

Next things to try (and why):

• Try a different router. Maybe the NDIS of Vista, or something in Vista has triggered something in the router to reject it and/or Vista has [suddenly] turned against my router (the mutiny!).
  Was unable to try a different router - seems I am missing a connector for my other router, although I doubt this is the problem anyway, since my laptop is working fine! 
• Try installing XP on the desktop. This will help localise two issues. Is it Vista, or is it the NIC's? If all works fine in XP, then I know its Vista, if not, then I know its likely the NIC's.
  I am relieved in some ways, since installing XP DID NOT fix the issue (I don't want to give up hope on Vista - I REALLY like it!), looks like this really is a hardware failure. When I try to go into the network adapters properties, it seems to take ages to load to (and XP is VERY fast on this rig). Good news, received email back from vendor to arrange return and replacement.
• Pray some more and reset everything again. What? Every little helps right?

Anyone else had the same issue? Did you manage fix it? How?