I'm not an IT expert, but maybe flushing your DNS may work?
http://www.tech-faq.com/how-to-flush-dns.htmlMost DNS clients cache the results of name resolution requests. This means that the DNS clients will temporarily store the website names that you have been visiting lately. This process speeds up name resolution if multiple lookups are done to the same address, such as is common when browsing the web. Hence, if you visit Yahoo.com second time, the DNS client will already have the name mapped and hence will retrieve the mapping quickly.
Sometimes a bad DNS entry will be cached and you will need to either flush the DNS cache to get rid of it, or wait up to 24 hours for it to be dropped from the cache automatically. Given below is a comprehensive step-by-step process to flush the DNS.
I wouldn't do anything until Letters or Jofhn says it's safe to do so though, because I don't want to damage your network connection lol.