Network adapter may be broken, Ethernet cable not detected

[James_438]

Background Info

■ I'm not very tech savvy, so please bear with me if I come across a little slow.

■ My computer uses Windows 7 64-bit as it's OS.

■ Recently moved house and my computer could connect through an Ethernet cable at the old house.

■ Firstly when I moved in to the new place, my computer shut down shortly after turning it on. From checking Internet forums it said it was likely that the motherboard wasn't connected well and told me to reconnect all the wires - this resolved that issue.

■ The connection in my new house is working, I've checked the wire in my room with my laptop which can connect to the internet through the wire (when I turn off the wireless). It seems like only my desktop has a problem.

Issue

When I plug the Ethernet cable to my computer, the Network and Sharing Center shows it try to identify the network, then it stops.

When I try to troubleshoot, it says the Ethernet cable is not connected. The computer sometimes goes through loops of trying to connect and failing.

Sometimes the computer will connect to the network, but say "limited connection" and the troubleshoot says both that the Ethernet cable may be broken and the Local Area Network doesn't have a valid configuration. The network would be called an "Unidentified Network".

I have already attempted reinstalling the driver for the network adapter following advice from other people's forum posts, but it wasn't successful. Also my computer said that it was already the most updated driver and there were no problems before I moved house.

Questions

Does anyone with more know-how have any advice for what I can try?

Should I buy a LAN card to connect to my motherboard and see if that works? (I'd rather avoid having to spend money if I can, so this is sort of last resort)

Is there anything I should know about buying a LAN card before buying it?

Thanks for your attention.

 

[jsmithepa]

With networking, you troubleshoot in multiple "layers."

First you must make sure the so called physical layer works. This is a fancy word for "is the cable solidly in contact with the RJ45 jack." If Windows is routinely telling you CABLE DISCONNECTED, and you get a circle-slash icon on the system tray, it means you are having a physical layer issue, and you must resolve this even before paying attention to anything else.

What can cause a physical layer issue? Bad cables, but I assume you already swapped the cable, is just a normal thing we all do right, right, so that' done. Why is the cable not making solid contact with the RJ45? A dust bunny in the RJ45 jack or bent pins, so shine a flashlight in there and look for anything abnormal. Does the cables CLICKS SOLIDLY into the jack? there should be no sponginess when you plug in the cable. Also the RJ45 typically has 2 tinny LED on each side, they signal you something, consult the manual see what they are telling you. For physical layer troubleshooting, the LINK LED (again consult the manual which one is which) should be solidly lit and never blink or go dark.

Now you don't want to do any of these, you can always use an add-on ethernet card and see if that works, if you have a card laying around, or buy another, is relatedly inexpensive but of course you have to install driver for it.

 

[James_438]

Is it standard practice to reply my thread by putting an answer here or editing my original post?

Anyway Re:jsmithepa, thank you for your response, I think you are right. There is a problem with the connection between my the port and the cable.

I'm quite certain it is not the cable as it works for my laptop, and I got my electrician to check the cable shortly after I moved in when I first noticed the problem. They said it shouldn't have a problem.

I will search for the manual to see what the LEDs mean but currently the LEDs flash every 2-3 seconds the green one for a long beat and the yellow one for 2 short beats.

The cable does click into place and the port doesn't seem dirty when I looked into it with a flash light. The pins don't seem bent, they all seem to be aligned (parallel).

I suppose at this point I will just try buying and installing a LAN card, I'll report back here if that works.

 

[The Paladin]

if you have a laptop, leaving it connected to your router where the desktop was in, plug it into laptop it it works fine, then your hardware issue is your network card on your desktop.

if you replug the cable into the desktop do you get any lights at your rj45 port ? you should in theory see 1 solid (left) and one blinking (if traffic is seen) what colour is the left one ?

 

[James_438]

Assuming the side of the cable with the clip is the top, then the LED to the left is green and the one to the right is yellow on my desktop.

My laptop doesn't seem to have LEDs at the Ethernet port. But when I plug the Ethernet cable into my desktop, the green (left) LED will flash every couple of seconds and in the same time that LED is lit (about a second), the yellow one (right) flashes twice.

I haven't found the manual yet, so I'll check that first to see if that means something specific.

My feeling is that the pins inside the cable don't all connect to the pins in the port so it's some kind of incomplete connection... but I don't think I could repair that on my own.

I figure it would be easier to get a LAN card to see if that works rather than taking my whole desktop to a shop to see if they can diagnose and fix my issue. So I was going to try a LAN card tomorrow.

My motherboard still has a lot of empty slots anyway as I only really have a graphics card directly into it. The audio and network stuff are all onboard, built into the motherboard itself. I think my power supply has enough power for a network card to be put in, so it should be fine.

Thanks for reading through and responding to my post!

 

[The Paladin]

Led on left is speed indicator, it should be green (100 mbs) or Amber (1gb) but neither of those colours should be blinking.
check in your device manager at the network devices, is that card showing working properly or has a yellow triangle ?

 

[James_438]

The device manager says that the device is working properly. There is no yellow triangle.

It also says that the latest drivers are already installed.

I tried to reinstall them already but that didn't help.

 

[The Paladin]

try another lan card I think is your way out of this.

 

[James_438]

Agreed! I'll look into buying one tomorrow and will report back here if it works or not.

Thanks for your response!

 

[jsmithepa]

1. Don't modify your original post (all forums anywhere). These forums are not private consultation service. Just like a radio call-in show, they service as a encyclopedia for the general listener. Modifying your original and the general public won't know how the problem started and benefit.

2. The LED pattern is different from NIC to NIC, so from desktop to laptop, don't automatically (even though human would think so), they signify the same thing. You must consult the manual of each. Yes it keeps us IT folks in the job. ^)

3. It takes 2 to tango. Don't forget the switch port the other end of that cable. THAT RJ45/port can have problem too. US, we automatically swap cable and automatically try another switch port. Did you?

But OK, enough of that. Lets hope a new board does it.