My computer won't recognize there is an Ethernet cable plugged in

I have a an Ethernet cable (that I have tested on my laptop so I know it works) plugged into my computer and the light blinks green in the back but it won't let me connect to the internet or even recognize a cable is plugged in. Any ideas on how to fix this?
36 answers Last reply
More about computer recognize ethernet cable plugged
  1. Does the switch or router port also light up?

    Some cards have green mode that causes the port to now work if nothing is on the other end. I have seen some times when this feature back fires if the router/switch has the same feature(they are both expecting a signal from each other).

    You should also ensure you have the latest drivers from the card or motherboard makers web site.
  2. P.S. : I've had this problem before and apparently the port was turned off and I was able to turn it back on by doing a diagnose and repair. But this time the repair doesn't fix it. Is there a way to manually check? If so how?
  3. It lights up where I plug the cable in and the router does too. I don't know much about computers :/ but I have a general idea of how they work
  4. Normally the Green Ethernet thing would cause no light, it looks like a dead cable(Green Ethernet, not your issue.)

    Has this computers network card worked in the past? Has anything been changed on the system like an OS reinstall.

    If it is older, maybe you have a crossover cable or something(some older hardware does not work right with crossover cables, while most new hardware will auto adapt to it).
  5. I haven't installed any new hardware or software.
  6. And it just stopped working one day or was not used in the past?

    Can you check to ensure the drivers are installed and maybe grab the latest from the board/card/system makers website and bring them over on a flash drive to install and see if it helps.
  7. Yeah it just stopped working one day and I fixed it like I had said earlier, but this time I can't fix it. I'll try to check if the drivers are up to date and I'll post my findings.
  8. Feel like a moron but how do I check the drivers are installed? I tried the downloading the latest from the makers but that didn't help
  9. You can check under device manager
    Start + R and type devmgmt.msc

    It will be under Network adapters.

    If the latest did not help, it may be something else.

    You may need to go into basics. I hate to recommend changing what seems to be a good cable, but we are running low on options.
  10. nukemaster said:
    You can check under device manager
    Start + R and type devmgmt.msc

    It will be under Network adapters.

    If the latest did not help, it may be something else.

    You may need to go into basics. I hate to recommend changing what seems to be a good cable, but we are running low on options.


    There's no tab for network adapters. Maybe that's the problem?
  11. Not under Monitors and above Portable Devices.

    That could be an issue for sure.

    Do you see any devices with a ? or ! on them?
  12. Nope no ? Or !
  13. And Windows can still tell you a cable is not connected?

    Should have looked something like this(guess I have no portable devices on this system :))

  14. Well it just doesn't recognize there is a wired connection and yeah it looks just like that but no network adapter tab. I should also note that it won't connect to the internet when I use my iPhones portable hotspot connected via USB
  15. I have never seen a lack of Network tab yet windows still seeing no cable(normally you do not even see that until the card is installed.).

    Can I get more system specs.

    What board are you running? I want to see what settings it has.
  16. Yeah I can get them if you explain how I don't know how to get the specs or know what board lol computer noob here.
  17. Well if it is a pre-built system(HP/DELL/Compaq/Acer/ect) the model number off the case should be all that is needed.

    If it is a custom built system you can use the Mainboard tab in cpu-z
    http://www.cpuid.com/softwares/cpu-z.html

  18. So the product #? That's kq495aa-aba otherwise it's the HP Pavilion a6500f PC I'm working on getting the mode now
  19. I have not seem HP system used any kind of green networking or anything. I know Nvidia had a strange setup in the past for networking(nforce firewall/ect).

    I will see how the network card shows up on an old Compaq since it was an older HP system as well(HP owns Compaq after all).
  20. Yeah it's a nvidia. Btw thanks for the help.
  21. I do not have good news. The older(XP system, but it has an Nforce based chipset and realtek based network card) system I checked DOES show network cards in the same spot as my newer systems.

    I almost have to wonder if some kind of hardware failure has happened with the onboard network card.

    What do you see

    If you felt adventurous, I would recommend trying a live CD/DVD of Linux. Live CD's do not install as long as you run them in live mode(they are not fast because they run off the cd/dvd, but they to work). They tend to have drivers for almost everything and at least if the network card worked on it, you would know it is a Windows issue and not a hardware failure issue.
  22. Well no internet seems to be the least of my problems. Now when I turn it on it just has a black screen. Yes the monitor is plugged in.. Guess the motherboard is going on it. Time for a new computer.
  23. Damn that is just bad luck.
  24. nukemaster said:
    Damn that is just bad luck.


    Lol that it is. Thanks for the help anyways
  25. goto device manager->network adapter->..double click on the " network adapter".. if there is already a" ethernet driver software" is installed then ..right click on it and "enable" it..or else "download" the driver software for ethernet cable ,which is also suitable for your computer. :)
    hope diz will help u out
  26. Hello nukemaster!

    I am writing into this (old) thread since it is the ONLY one I have found - after hours of searching - which resembles my issue...
    I am not even sure if this thread is still 'active'/ whether I should start my own thread!
    But seeing your detailed responses encouraged me to give this a shot...

    My issue: (well, the present one, anyway!)
    [Unlike the original poster's problem, where Erice1996 reported that the computer "won't recognize there is an Ethernet cable plugged in"]
    [But just as Erice1996 reports later,]
    My Device Manager doesn't even show a Network tab.

    [And also, as with Erice1996's issue]
    My problem(s) seems to have developed ever since I upgraded to Windows 8.1 (Everything was fine while I was with Win XP!)

    I have a 'home-built' Desktop Computer (I am not a geek, just someone who has to run a rural organisation in India where nothing is accessible and very little funds at hand - and also, someone who enjoys DIY'ing)

    Specs:
    • Motherboard:- Intel Desktop Board DG41WV - Essential Series - motherboard - micro ATX - LGA775 Socket - G41 (Here's a CNET link with the specs)
    • Onboard Gigabit Ethernet:-Integrated 10/100/1000 Network Connection(The onboard chip is too small to read clearly - i think it reads...) REALTEK RTL811DL
    • OS:-Windows 8.1 Single Language (English) 32-bit - Full Version (OEM)


    There are OTHER errors that have been occurring lately - which were probably triggered by my rural-staff not shutting down the system properly, while I was away (they were constantly 'hard booting' to shut-down, with the power button, as they could not find the 'Shut-down' command as easily on the 8.1 interface!)...

    I can give you a step-by-step of all that has been happening - but I am not sure whether that is required at this moment.
    [The BIOS was not loading, to begin with... CMOS jumper re-set etc. did not help - three-beeps heard even before post - so, I searched and found that this was a RAM failure notice - opened and re-set the RAM... changed it's port... finally, a thorough rubbing of the RAM terminals, and violla, system was up and running!]

    The basic issues at the moment are:-
    • CMOS CHECKSUM ERROREvery time I power off and start the system again, POST shows CMOS checksum AND Battery failure error.However, the battery shows 3.02 V on a Digital multimeter - and the battery socket seems fine, at least from the top-view of the mobo.
    • Device Manager does not even record a Network adapters tab!!!(Even after I try connecting my modem/ laptop with the Rj46 cable)However, when I connect the same modem with the (optional) USB cable, the Network adapters tab appears - showing "USB IAD LAM Modem" details!At this point, if I choose to 'Show hidden devices', a long list of (mostly) 'unselected' items are displayed - but NONE OF THEM look like the one I need - for example, there's none from Realtek - though there are a number of 'WAN Miniport' items.


    I have already tried a number of remedies (which I will gladly narrate, if you ask for it)...
    Howerver, at this point I have a feeling that I need to first check whether the onboard LAN is shot, or is it a BIOS settings/ OS compatibility/ driver issue...

    In your last note to the original question you had mentioned something about "trying a live CD/DVD of Linux"... Can you please help me to - (1) understand what you mean by that - (2) guide me through the process?

    Or, do you think I should try something else??

    Thanks in advance...
    Cheers!


    nukemaster said:
    I do not have good news. The older(XP system, but it has an Nforce based chipset and realtek based network card) system I checked DOES show network cards in the same spot as my newer systems.

    I almost have to wonder if some kind of hardware failure has happened with the onboard network card.

    What do you see

    If you felt adventurous, I would recommend trying a live CD/DVD of Linux. Live CD's do not install as long as you run them in live mode(they are not fast because they run off the cd/dvd, but they to work). They tend to have drivers for almost everything and at least if the network card worked on it, you would know it is a Windows issue and not a hardware failure issue.
  27. A 2032 battery like in a computer may have a voltage drop under use that does not show up on a multi meter. If you can measure it while installed in the holder you may get a better idea.

    Most bios on some boards will also allow you to see the battery voltage.

    For the price it may be worth at least trying a new battery.

    As for the try a live CD/DVD

    A live CD/DVD is just an operating system that runs from a CD or DVD. Because of this it can not have any changes made to it, but it also somewhat slow. I reason I suggest this is just to see if Windows is the issue or the hardware it self. Many live versions of software can now run from a USB stick as well.

    Setting it up is as easy as burning an ISO image.

    With the disc burned you can just tell the bios to boot from that disc. In live mode it will NOT effect anything on the computer. These live discs have drivers for almost everything so that is why they are good for testing.
  28. Thanks a tonne for your prompt response!

    Will get back after I follow-up on your suggestions...
    At the moment we are encountering massive power-outs, thanks to disturbances in the rural electrical-grid. So, I'll probably need a couple of days.

    Cheers!

    PS: One small clarification:-

    While checking-out your suggestion of testing with a live CD/DVD of Ubuntu, I am finding more than one options...
    [Like this page from 'ubuntuforum' lists TWO OPTIONS]...
    <<
    1. Run a live session booted from a CD/DVD/USB drive and select 'Try Ubuntu without installing'
    a. Basic install drive (live drive)
    b. Persistent live drive
    >>

    I am assuming that option "a. Basic install drive (live drive)" is what I need, right?

    nukemaster said:
    A 2032 battery like in a computer may have a voltage drop under use that does not show up on a multi meter. If you can measure it while installed in the holder you may get a better idea.

    Most bios on some boards will also allow you to see the battery voltage.

    For the price it may be worth at least trying a new battery.

    As for the try a live CD/DVD

    A live CD/DVD is just an operating system that runs from a CD or DVD. Because of this it can not have any changes made to it, but it also somewhat slow. I reason I suggest this is just to see if Windows is the issue or the hardware it self. Many live versions of software can now run from a USB stick as well.

    Setting it up is as easy as burning an ISO image.

    With the disc burned you can just tell the bios to boot from that disc. In live mode it will NOT effect anything on the computer. These live discs have drivers for almost everything so that is why they are good for testing.
  29. I would recommend try without installing, but livedrive is an option I have not even looked into.
  30. Hello again, nukemaster,

    ...

    To begin with, let me apologise - this is going to be a long one!

    General observations:-

    APPARENTLY, MY BIOS DOESN'T READ MY SYSTEM/ MOTHERBOARD AT ALL!!!



    In the BIOS menu...
    Advanced> Hardware monitoring> (values are being displayed for) Processor thermal margin/ Motherboard temperature/ +5v, +3.3v, +12v/ Processor voltage etc...

    But, in the menu section...
    Main> Additional system information> System information/ Desktop Board/ Chassis Information sections ~ Manufacturer/ Product name/ Version etc ~ ALL SHOW *BLANKS*!
    (My MoBo seems to be an 'OEM version' - and I think I read in an Intel support page that 'third-party' modifications may exist in such boards)

    As soon as I turn on the UPS power, when the MoBo power-LED comes on, (before i hit the system power button) - both the signal lights above and below the LAN port come on - and stay fixed - one amber and one green.



    developments:-


    After I re-set the CMOS jumper one 'last time'- this was probably the 6th time I was trying that to see if anything changes - and re-started the system, the CMOS checksum & battery failure errors have magically vanished!!

    I have powered-down and restarted a number of times after that - and still no error.

    The only difference I can think of, between my earlier attemps and this one, was that I had casually pinched down on the battery holder clip this time, just to check that it was tight enough.

    Incidentally, as per your suggestion, I checked in the BIOS settings, and yes, indeed, there was a section showing the (3.3V) battery voltage - and it was displaying as '3.236 V'.

    I had tried to load the LAN drivers in the software CD provided with the Mobo earlier - but that had repeatedly failed - with the same issues reccuring everytime.

    Now I located my particular
    LAN (model) controller
    on the
    Realtek site - and found that there was a Windows 8/8.1 specific versions of the driver package - which I downloaded.

    But the exact same issues were repeated when I tried to run this new driver!

    What happens is this:-
    The Realtek driver install window opens> 1st screen asks me whether I want to *Install/Repair/Remove* the driver (I have tried both Repair & Install, after Remove)> Install shield wizard starts the process, (the *Remove* works smoothly) copies 'updated files', with a top-note saying *...is repairing Realtek Ethernet Controller Driver*> then it begins to 'search for a Realtek Network controller'...

    ... AND, DAMN! A new pop-upopens - with the message *The Realtek Network Controller was not found. If Deep Sleep Mode is enabled Please Plug the Cable*

  31. It depends on the board, One of my boards had a feature in the bios called green Ethernet or something like that and with it on, my network card would disappear unless it was connected to something.

    Now this was more complicated because I have a Dlink green switch that shuts off ports when not connection is detected. Because both devices turned off and just sat waiting for another device switch them on, I had no network at all with the feature on.

    Using my older non green switches also solve this issue, but thankfully, I could disable the feature in the bios.

    The part about information to be filled by OEM is pretty common on many boards like that.

    Does the card show up in the device manager? Hold start(winkey between alt and tab) then R on the keyboard. In the next window type devmgmt.msc and hit enter.

    Look for your network adapter.

    It should look something like this. Keep an eye out for yellow exclamation marks and stuff.
  32. nukemaster said:
    ....
    Does the card show up in the device manager? ...
    It should look something like this. Keep an eye out for yellow exclamation marks and stuff.



    Do you mean whether the LAN card shows up on the device manager?

    No, it doesn't - that's the problem - from the start!

    No yellow flags iether.
  33. If you do not see Network adapters listed then you have more problems for sure.

    Please ensure the bios does not have a green or other power savings feature for Ethernet(because those shut it off before the OS loads.).
  34. Hi,
    Thanks again for your inputs.
    I can't locate any such 'switch' within the BIOS screens - there's only one option related to the LAN, apparently - that of 'enabling/disabling' it - and I have it enabled.

    One thing that strikes me as a bit odd is that BOTH THE LAN-PORT SIGNAL LIGHTS come on - and stay on - as soon as I turn the power on - even before I actually switch on the computer. Is that NORMAL?

    nukemaster said:
    If you do not see Network adapters listed then you have more problems for sure.

    Please ensure the bios does not have a green or other power savings feature for Ethernet(because those shut it off before the OS loads.).
  35. Yes many boards do this.

    Some computers allow you to power them on over the network(good for a business, but I have never used such a feature).
  36. I have the same issue on one of our machines. It's a acer with Realtek driver. I can't even reinstall windows update as something has shafted that also. All checks say everything is working but the network simply doesn't show and there is no access.
Ask a new question

Read More

Networking Computers Ethernet Card Cable