I think I know the cause of the problem, but am looking for a solution.
I found this discussion trying to resolve my issue with DNS. I too have a Sonly Laptop running Vista Home Premium and Trend Micro. My computer keeps losing my DNS setting - which is to "Obtain DNS server address automatically." But it keeps switching to a static IP address. This means my machine cannot resolve IP addresses and I cannot connect to anything.
It is just doing this on the LAN (wired) card and the wireless keeps working. I keep wireless turned off most of the time, so usually I cannot connect. It just so happens that today the wireless was on and I noticed that I was loading pages much slower. When I turned the wireless off, no connection at all.
When I looked at IPv4 properties, it was clicked for a fixed IP address (which was not a DNS server) so no addresses would resolve.
So, can anyone help with that problem. I think it is the same one everyone here is experiencing.