If things worked BEFORE ESET, try uninstalling it.. We're seeing a number of such problems with various antivirus suites.. It can be a compatibility problem.. or a firewall issue that conflicts with the Windows firewall (confirm there is only one firewall running)or a number of other things.. Uninstalling it should tell you whether the program is the culprit..

Another frequent culprit is outdated modem or router firmware. Vista seems to "need" the most current firmware. Check the website for both devices and download and install the most recent firmware. The DNS Configuration error seems to lead in this direction....

Hope this helps.