PC Keeps dropping Network Connection

dercoss
dercoss used Ask the Experts™
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I have a small network running Small Business Server 2003 with a few client pc's. The clients are all XP with SP2 installed. One of the pc's keeps dropping and then reconnecting the network connection every now and again.

It seems to be only this one pc with the problem as I have tried accessing the same shared files on the server from  other pc's without trouble. I have changed the network card and ethernet cable and have reinstalled the networking software without success..

The only clue I have is that the onboard ethernet connection on the Elite Nforce4 board recently stopped working and I replaced it with a pci card. I got the problem soon after. I have tried various ethernet cards without any change.

I am using the latest motherboard bios and drivers.

Do you think the motherboard has a fault?

dc
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Commented:
Have you tried going into Device Manager to disable the onboard card and just use the PCI card? Perhaps there's some sort of conflict going on.
Top Expert 2006

Commented:
Make sure that Spped and Duplex is set to AUTO.

Also, make sure Power Management is not set to turn off the device to save power.
I would change what port on the hub that PC uses,
and set the cards speed to link speed of 10Mbps/Half duplex for troubleshooting.
If the problem goes awat bump the speed to 100Mbps/Half duplex.
Still OK go to 100Mbps/Full duplex.

Some switches have a hard time with the auto negotiate setting.
Paul WalshSystem Administrator

Commented:
Also, try the card in another pci slot

Author

Commented:
Well, changing the card speed to 10Mbps/half duplex solved the problem. I can go to 10Mbps/full duplex but not 100Mbps. I have tried 3 different cards now with the same problem.

Is there a way of getting the 100Mbps back?

dc
How old is the hub/switch?
I have run into issues with older network equipment that does not handle autonegotiation well.
The only solution I have found is to define speed settings directly.
My experiance shows that if this is the case you may see other PCs starting to have these issues over time.

I have had to replace the hub/switch in order to fix these problems.
On the bright side 10/100 switches are really cheap now.

Author

Commented:
It is an integrated Netgear DG834 Modem/Router with 4 ports.

dc

Author

Commented:
I've tried swapping the cables to different ports but it is always the same pc that has the problem. I have tried completely different cables without success. It seems to be a problem specific to one particular pc rather than the router..

dc

Commented:
Have you disabled the onboard card and removed it from device manager?

Do you have both interfaces connected to the network, if you do unplug the bad one.

Do you have any drives that were mapped through the old interface?  Try deleting them and then remap them through the new interface after you delete the old one.  

Do you have a networked printer?  Delete it also and recreate it.  

What else is running on the PC? What does task manager say your CPU is running at?  If it is high have you checked for Malware and Viruses?
It could be the cable. Not that the cable is totally bad, but iy may have dropped out of spec for Cat5.
If you have a dropped celing and the cables run over it, you could have a cable running accrss a flourecent light.
Heat from a light, mice, heat from ducting, etc.. can degrad cable quality over time. Also I have seen the terminators in the wall go bad causing poor connections.
If you can reach with another cable, run a new cable to the router.

Another option for troubleshooting is to boot the PC with Bart PE and enable networking to see how the connection holds up.
If you still have issues then at least you know it is not your Windows installation.

http://www.nu2.nu/pebuilder/

Commented:
try doing "sfc /scannow" to check for altered file, be sure to you're current with all updates (drivers, windows), in safe mode scan for any viruses or spyware problems,

Author

Commented:
I've disabled the onboard card and it no longer appears in Device Manager. No Networked printer. CPU is only idling. Full Virus and spyware scans show the system is clean.

I've swapped the cables over to no effect.

I'll try running system file checker now..

dc

Author

Commented:
Still no difference after running sfc...

dc

Commented:
Ok try typing from a command prompt "net use * /delete"  answer yes if prompted.  

Author

Commented:
I did that. What should it do or show?

dc
Go pick up a $50 switch and plug all of your devices into it.
Make it your central point.
If your problem goes away, your done. Of not, return the switch and you know it is software.
You need to work methodically to eliminate possibilities, and replacing a switc on a amall network is quick and easy.
I donn't like all-in-one solutions anyway, a seperate switch and router usually is better and more flexible.
As an admin, tour time is more valuble than a $50 switch.

Author

Commented:
I'll give it a go but I don't see it can be the router as as I said, the problem remains whatever port I use but only on that pc...

dc
I have seen this happen with switches before, but it is more about eliminating possible problems.
If I am troubleshooting a problem, I alway start with the easy, fast solutions first. If they fail to resolve the problem, then go on to the more dificult/time consuming/expensive options.
That said;

I have had this exact problem where only one client is having an issue. I took the same steps you have taken. Software, NIC, even went as far as reinstalling Windows. Within the year the problem spread to other computers, and when I replaced the switch, all was better.

I know there are other things that could cause the same symptoms, but swaping out a switc is a 15 min. job, so its an easy thing to try. If it doesn't work, at least you know it wasn't the problem, return the new swich, and you haven't lost anything, but you have gained one less possibile issue.

Author

Commented:
Well, I've managed to get to the bottom of the problem at last... The motheboard must have been faulty because a few days a go the pc started cutting out and eventually failed completely. I changed the board and since then the network problem (and the cutting out problem) have not returned...

dc
Closed, 500 points refunded.
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