pc so busy on lan it and others can hardly use adsl

  elcaro 17:18 03 Jan 2013

Hi all, Just joined. I wonder if anyone could help please? I've got an ADSL router and various computers connected by ethernet and wifi to it. All seems well until a particular PC is connected. Then everything goes slow and streaming becomes impossible. For example the BBC iPlayer speed tests, which previously looked ok, return very low figures for that PC, and for the other computers as well. I've tried the PC via wifi and via ethernet cable. I attached the PC to a couple of different ports via ethernet and their lights on the adsl looked very busy. When the PC is attached via wifi the adsl port for the wifi looks busy. At the PC, when on ethernet. there is a white light and an orange light at the ethernet socket. The white looks to be on solid and the orange light almost solid. It looks as though the PC is trying to do something which is hogging the LAN, but I don't know what. From looking at the packets going out from the adsl, I don't think this traffic is going out to the internet. Wireshark doesn't show many packets though from what I can see. The PC wasn't doing this until recently. Recently it was moved to a different house and therefore from a bt home hub to another provider - but it has been used many times on the past when the owner has visited here, without this issue. I would be grateful for any suggestions about how I could find out what's happening and stop it. I'm not very experienced with PC's I'm afraid. TIA for any assistance. - Terry.

  Woolwell 17:33 03 Jan 2013

Is it downloading windows updates? Is the anti-virus/firewall up-to-date?

  elcaro 17:42 03 Jan 2013

Thanks Woolwell for your prompt reply. Downloading windows updates - I don't know - the situation has been going on for days, or at least any time that PC is connected, and sometimes (before we realised there was a problem) it was connected for hours, so it should have finished if it was downloading stuff. the AV looks ok, not sure about the firewall. I was using Wireshark on another computer on the lan, and I found out today that if you set Wireshark to "capture in promiscuous mode", it ain't necessarily doing that, so my intention is to try Wireshark on the actual PC itself as soon as I can - would that make sense? i'm hoping that there is some service ot task which we can just stop to get round this, don't know. Thanks, Terry.

  Woolwell 17:51 03 Jan 2013

OS of the problem PC?

  Secret-Squirrel 17:57 03 Jan 2013

The constant network activity could be due to something innocent like a P2P (file-sharing) program that's running in the background. More worrying, it's possible that the PC's been hacked into and is now a "spam zombie", or worse.

"the situation has been going on for days,"

Because this problem's so recent, the quickest and easiest potential fix is to run the Windows System Restore utility. Choose an available date that immediately pre-dates the start of this problem. If you're unfamiliar with it then let us know the version of Windows that's on the problem PC.

Additionally, or instead of, run a couple of effective free malware removers such as Malwarebytes and HitManPro to make sure no infections are present.

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