Win7 says no ethernet cable is connected - it lies!

Hello all - first post!
My internet worked fine for months until about 3-4 weeks ago I stopped grabbing a connection. The link light on my modem (Linksys CM100) doesn't show a connection, though it says I'm online.

Win7 says I don't have an ethernet cable connected and I've tried 3 different cables (all known good and tested) and still nothing. I've added a PCI network adapter (known good) stripped from my other PC and still nothing. Both the onboard and the PCI card will show lights, and my PS3 (wireless as well as wired) can even connect to my computer and stream music and movies. Win7 still says no ethernet cable and limited connectivity. If I bypass the router and home run from wall>modem>PC, I don't even get limited connectivity.

If I have the link light (rare, and doesn't necessarily mean I'm connected to the internet) and I power cycle either the modem or the router, I lose the link, end of story.

Any idea what's going on? If Win7 says I have no ethernet cable connected, why can my PS3 see my computer's files? All drivers are installed properly and according to Win7 are functioning fine. I'm at a loss as to what to do. Could there be a problem that popped up overnight with my 7 install? Wiping and a fresh install is definitely on the books at this point.

From what i understand you've doubled checked the ethernet cable from the router --> PC.
Have you tried checking the cable from the router --> modem?

The router itself could possibly be the issue.

When you bypass the router all together, what happens? Im a bit confused, No internet access at all that way either?

Have you tried:
Unplugging the power from both the router and modem, wait 45 seconds and reboot them.
Then after the reboot, run a network diagnostics.

Bypassing the router does nothing but take the computer out of the network - instead of limited connectivity I get nothing. I called my ISP and they said my router is fine and it shows that I am, in face, online and all is behaving normally (no packet loss, etc). I think the issue lies in Win7 because I can connect my PS3 to the network and still access files while Win7 says I have now ethernet cable connected (my PC is wired into my router). The only thing I can imagine being wrong with the modem is that for whatever reason, whatever looks for a link between the computer and modem is busted. Not sure how because it hasn't moved since I installed it.

Sadly, I am not very knwledgeable in network troubleshooting.

The only advice I can give ATM, is try rebooting them both and the run the network diagnostic from the control panel.

Control panel->Network and Sharing Center->Troubleshoot Problems

This has typically worked for me with some issues.


Hopefully someone with more knowledge and experience with such issues will be along shortly to help you.

Try uninstalling your network adapter drivers, and installing the latest version. Perhaps your current drivers are buggy.

I'd love to, but no internet connection to find them again! No idea where my mobo CD went to for the onboard and the PCI card is old - it's driver CD has been gone for a few years now. I was able to do it once on the rare occasion I came home and found it with a connection. I uninstalled the drivers on both and reinstalled. It just up and lost connection (I wasn't even on the computer when it happened!) about an hour later.

Go ahead and download them from the internet, and burn them to a CD or copy them to a USB drive.

We've had this kind of thing happen a couple times at our place...

Generally all machines are affected in some way with limited or sporadic network performance.

The issue is generally that /somewhere/ on the network is a bad component or cable causing noise or garbage on the line. Rememeber that until you hit a switch, all machines and adapters are all sharing what is essentially a single signal wire and anyone with bad hardware can take out everyone else on that loop with noise or congestion.

Usualy it comes down to a bad hub or a bad adapter somewhere. Or possibly a cat chewed cable which doesn't even have to be the one connected to your computer. Could be somewhere else in the house...

punkn00dlez said:

I'd love to, but no internet connection to find them again! No idea where my mobo CD went to for the onboard and the PCI card is old - it's driver CD has been gone for a few years now. I was able to do it once on the rare occasion I came home and found it with a connection. I uninstalled the drivers on both and reinstalled. It just up and lost connection (I wasn't even on the computer when it happened!) about an hour later.

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You can help us to help you by filling out your System Specs.

Following program is my personal choice for gathering the necessary info:
SPECCY- System Information Tool
http://www.piriform.com/speccy

FREE. Operating System, CPU and Temp, Ram, Motherboard, Graphics, Hard Drives, Optical Drives, Audio, Peripherals, Network info.
Simply put—this is the best and it’s free!

I'll fill it out tonight once I get home. I just couldn't think of the specific models when I registered.

fseal - no cat chewed wires. He doesn't go in my computer room - he blocks my monitor so I put a stop to it. No dogs either. The only wires I'm using are from the modem to the router and from the router to my PC. I wonder if I can snag a wifi card from our folks' house...that'll help figure out what's going on...especially if I can connect at that point. I'm not ruling out a bad component, I just haven't been able to find it yet.

This is unlikely, but I'll throw it into the mix anyway.

Most routers/hubs have one port designated for connecting to another router/hub... did you somehow get plugged into that port? If so, try one of the other ports.

Make sure Windows is trying to use the correct Internet connection. Sometimes extra stuff gets in your list of available connections and Windows wants to use the wrong one.

Also, lots of motherboards have two NICs built in these days. If you only use one of them you'll probably want to disable the other one in the BIOS, else Windows will always remind you that there is nothing plugged into it. If you've already done that, make sure you have the cable plugged in to the right one. (Done that once myself...)

Darwin - Nope. I'm plugged into port 1, and my PS3 used to be plugged into port 2 when it sat next to my computer. Other than the power plug, the only other ports are 3 and 4. My "from modem" is labeled "Internet", so that's pretty hard to screw up.

profdlp - I've disabled both connections at one point or another from within the OS. My mobo only has 1 onboard, I haven't thought of disabling it through my BIOS. I'll post back later and let you know how that goes.

I fixed it! I found something while picking Google's brain, and I'd love to share it with y'all!

This worked immediately for me without rebooting...I obviously rebooted anyway.

Reset WINSOCK entries to installation defaults: netsh winsock reset catalog

Reset TCP/IP stack to installation defaults. netsh int ip reset reset.log

Reboot the machine.

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Thanks for sharing the solution with us and glad to hear that you're up and running.

No problem. Thank y'all for your patience and knowledge. I see there's a lot of similar problems on here about ethernet cables not being seen.

I just got Speccy, and it's pretty much awesome. Thank you.

Glad to have been of help.

Nice to hear you got it sorted out & thanks for sharing the solution.