LAN ports not working Windows XP

[Tuwoki]

Hi, I have a client who has a desktop (Dell something) running Windows XP. She reported that the LAN port is no longer working. Did the usual over the phone tests (change cables and router ports, confirm it works on another computer) and it appeared to be limited to the particular PC.

Thinking that the LAN port is dead (surge/spike?), I did a quick visit while on another job and established the following:

- The builtin LAN port when no cable is connected is active and blinking. The Windows XP network connection indicates that it is searching for a DHCP server and eventually self assigns (yes with no cable connected)

- Plug in a LAN cable is the port goes dead instantly and Windows XP indicates no cable connected. Unplugging the cable and the LAN port goes back to the above point

- Uninstalled, restarted, reinstalled the LAN port drivers, same

- Installed a PCI Ethernet card, but no reaction when connecting a LAN cable. Tried different PCI ports, cables, ports on the router. XP indicates no cable connected. Confirmed the card worked in another XP machine onsite.

- Not having anything else with me at the time, I did a system restore back 2 months thinking if it is a software issue (maybe a bad DLL/Windows/Driver Update?) this may fix it, but no difference.

- Disabled the onboard LAN in BIOS and disconnected/pulled everything not essential from the system (additional PCI cards, DVD, etc) and again same problem.

- Mem test showed no issues

- Thinking that more likely a hardware issue, maybe PCI but the PC also has a Firewire and TV card which confirmed working fine (tried the ethernet card in both those slots and same problem)

I am doing a revisit next week to try a bootable copy of XP or/and a USB-Ethernet adapter.

Has anyone seen something this before?

 

[Knightsman]

I would say bad board, thats a bit odd for it to be blinking without anything plug in. Make sure there isnt and dust in that machine. Reinstall the drivers just to make sure. But bad board

 

[Xander]

Booting to a live CD will be your best diagnostic in a case like this .... so long as it's a comfortably generic part that the CD can identify.

 

[Aescaepulus]

Did you eyeball the jack? I found a piece of jewelers wire wedged in one once. After checking for FOD, I'd get into the BIOS and disable the onboard NIC, un install the drivers, and flush the DNS cache before plugging in the PCI card.

I think it would be strange that the PCI card wouldn't fix the problem as for the most part the onboard NIC doesn't use the PCI bus, and the other PCI devices work on the bus.

If that doesn't work, I'd do a Hail Mary and reinstall the NIC and mobo (system) drivers from the Dell support site and see what happens. After that I would give up and start talking about a new mobo.

 

[kevinjhaag]

I agree... Check the jack and make sure nothing is in there shorting out the pins. I would also test it with a linux live cd, or a winpe bootdisk. I have ran into nic problems before and it was something in windows that wasn't working correctly. It even still wouldn't work after a malware cleanup so I just N&P windows as I last resort and it was working just fine after that. Can't nail it down but something in windows was broke even thou the computer was working perfectly fine. Other than this, I would consider the motherboard faulty.

 

[ArtemusComputerTechnology]

Use a boot disk and run a diagnostic on the hardware and see what the results are.

 

[Techlogon]

Never come across your exact situation but suggests that pci slot is dead (try another?) or Windows networking is corrupt - self assigning (should be 0.0.0.0) without a cable is odd - reset TCP/IP stack.

Try a boot disk to confirm. USB-LAN adapter is a cheap and cheerful way of resolving if it's a bad pci slot/mobo.

 

[jogold]

If you move the hd to an identical system you can see if its the windows installation that is at fault and if you boot from a pe disk like ubcd4win or bart you can see if its the hw.

 

[Tuwoki]

Thanks everyone for the advice. To close the thread and be friendly to forum searches:

- PCI ethernet card doesn't work in any of the PCI slots. In saying it does not work, Windows sees the card, drivers install fine, but no recognition of a Cat5 cable connected. Cat5 cable works fine when connected to my laptop and a Firewire card works fine in all the same PCI slots. The PCI ethernet card also works perfectly in another Windows XP box.

- Tried a WinPE CD and the exact same thing happens, so I am happy to rule out a corrupt Windows install and that it is some sort of weird hardware issue.

- Installed a USB-Wifi adapter and networking works again (at least temporarily, didn't have a USB-Ethernet adapter) and gave the bad news of needing a new motherboard.

Maybe an hardware interrupt clash, but BIOS does not give any indication of such and the same still occurs if you disable the builtin LAN port in BIOS.

I am going to lose sleep over this trying to come up with an answer because it just does not make any sense!