My father's machine is running an up-to-date Windows Vista.
He moved to a different ISP. He had no network issues with the previous ISP.
When he moved, I got his computer connected to the new ISP (RoadRunner). At that same time, I removed some of the software he had installed including TrendMicro that his former ISP provided. I installed AVG free to replace it.
He started complaining about his connection coming and going. I also noticed this remotely via instant messenger because I could see him connecting and dropping every few seconds.
My method for reproducing the problem is to open a cmd and ping -t his gateway (default route). There will be several successful pings in a row and then some "Request timed out" or "Destination Host Unreachable". Often, the successful reponses immediately around these are very long -- seconds.
So, I started wireshark to watch what was happening during this test. I can still see all the traffic on the other side of the NIC -- NETBIOS requests for who is, etc. During the failed pings, wireshark doesn't see any outgoing requests. This led me to believe it's some software on the machine blocking the outgoing requests.
I've removed AVG -- no change. I've shutoff the firewall -- no change. I tried a different NIC (the machine has two) -- no change.
When I reboot, I immediately start up a cmd window and ping and for quite a while it's fine and then the dropped packets start. My father's user is non-privileged. The privileged user sees the same problem.
I tried booting Knoppix, it doesn't have the problem.
I tried booting into Safe Mode with networking, it doesn't have the problem.
Any advice you can provide would be greatly appreciated.