I started to notice that Zen's DNS servers were not responding to some queries, this was completely random and I only noticed it as some sites I knew were ok (like my bank) didn't come up.
I am running Windows 7 Pro and the new PC is linked to the router with an Ethernet cable.
DNS cache is flushed and DNS client disabled.
The event viewer showed there was an issue, even placing the IPs directly in the connection settings didn't fix the problem.
Switching to OpenDNS cured it so are there some DNS issues at present?
Note: I don't lay turf for anyone. astro or otherwise, all views and opinions expressed are my own based on experience.