Intermittent Network Problems in Vista

By forkmedia ·
I'm having a problem with an intermittent network connection that appears to be software-related in Windows XP, Windows Vista and Windows 7 RC1. When looking at the Network and Sharing Center control panel window in Vista, you can watch the connection icons show green links for a few seconds, then the link to Network to Internet becomes a red X, then the Network icon disappears completely and the link from the Computer to the Internet shows the red X. I also occasionally see a yellow warning icon between the Computer and the Network. It occurs with enough frequency to appear like an animation. In XP, the Local Connection Status window pops up every few seconds warning that the connection was dropped.

HP m7750N with AMD Athlon Processor 64 X2 5000+ 2.6 GHz 2gb RAM
with nVidia nForce Networking Controller

This computer ran Windows Home Premium for about six months and then I added SP1 in July 2007. Internet and Local Network connections (100 mbps wired) worked fine -- I could surf the web and share files on the local network via a Westell/Verizon DSL modem/router combo. About three or four months ago the computer started randomly losing the connection to the Internet and Local Network (sometimes only the Internet, sometimes both Local Network and Internet). I believe this may have been caused by an automatic Windows Update but there have been so many since I realized that may have caused it, simply deleting them one by one was no longer possible. Going through the normal Vista diagnostic steps did not resolve anything -- often the network comes back on during the diagnostic, and it will say there wasn't any problem. If the problem persists during the diagnostic it says it's fixed though it isn't.

Nothing had changed in my network. Other computers on the local network do not have a problem with local computer-to-computer or Internet connections.

Over the past few months I googled variations on "Vista networking problems" and tried suggested software fixes. Nothing worked.

Tried turning off IPV6
Tried the regedit fix on DHCP flag.
Tried power save off on NIC.
Tried disabling the BFE service.

One forum poster recommended turning off Auto Negotiation and using the correct duplex but I don't know what that duplex setting should be, or how to find out what it should be.

I also played with other settings in the Local Area Connection Properties window but never found a combination that worked.

For grins, I replaced the existing Ethernet cable with a cable that worked on another computer. As soon as the new cable was inserted it would light up for a few seconds, then go dark for a few seconds, then back on, same as the old cable.

I had a copy of Vista Business that Microsoft had given me as part of a promotion so I installed that on the reformatted hard drive. It seemed to work (after only a few hours use) until I upgraded to SP1. Now it's the same intermittent problem. I then installed Windows 7 RC1 in a dual boot setup and got the same problem. I even installed XP. Same problem. After the installs the computer had no third-party software, so that eliminated those possible conflicts.

I considered changing to a dedicated IP but not sure how to do that without affecting the rest of my network -- the Westell/Verizon modem/router uses DHCP to assign addresses and though it usually tries to keep the same addresses for each machine, occasionally they change.

I suspect the real culprit is the nVidia nForce Network Controller or its driver. I have reinstalled the driver and also tried to install an older driver but Windows always updates the old driver to the existing one (version, probably from the DriverStore folder) on reboot. I also used Windows Update to find the latest driver from Microsoft,, and installed that. It took several tries to complete the download because of the constant dropouts but after installing and rebooting, the new driver did not fix the problem.

Any suggestions that I haven't already covered?

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One thought

by BFilmFan In reply to Intermittent Network Prob ...

Set the NIC configuration for bandwidth to 100 MBps Full Duplex and let us know if the issue is better, worse or unchanged.

Also, I recommend that you drop on by http://www.speedguide.net/ and pick up the TCPIP Optimizer and let it adjust your NIC.

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Still not working

by forkmedia In reply to One thought

I followed your suggestion and changed the NIC settings from Auto Negotiation to 100 MBps Full Duplex. The network connection still flickered on and off.

I also went out to speedguide.net. I first downloaded the SG Vista TCP/IP patch and installed it, but no joy. I then downloaded the SG TCP Optimizer and ran it. At first it appeared that the optimzer had worked, but it apparently was only an improvement in the amount of time between dropouts. I'm now able to download small files in one session without having to restart/resume the download. But larger files (like IE8 via Windows Update) take repeated attempts. Luckily Update starts each time from where it was interrupted.

I'm considering dropping $30 and buying a new PCI network adapter -- I read elsewhere that people experiencing my problem did have success after installing a new adapter and the adapter's software -- though I feel certain this networking problem is simply an nVidia nForce software conflict or setting.

Thank you for your suggestions.

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Fixed It

by forkmedia In reply to Intermittent Network Prob ...

I installed a new Intel Pro/1000 Network Adapter (around $30 on Amazon). That solved the problem. The local network and Internet started working right away.

One glitch:
I inserted the Ethernet cable into the new card, leaving the nVidia opening empty, disabled the nVidia software/hardware, installed the new Intel driver for the new card from the CD and updated it online but my Network Control Panel window now lists "Multiple Networks". The nVidia adapter refuses to go away. I guess I'll just have to live with it.

BTW, when I booted the same machine from XP, and did the same install/unisntall, only the "Intel" local network shows up.

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