I'm not overly computer literate though. When you say "Open a DOS box and use nslookup to test your DNS", can you explain this?

When searching for a solution yesterday, I came across a thread in which one poster suggested the following:

"Start->Run->type cmd then in the command prompt, type: ipconfig/flushdns . Solves this issue about 80% of the time."

It did not work for me.