Restart router and PC. In that order.
Bob
Many thanks for the reply guys. But there is something not quite right here. I have tried the other 3 browsers (IE, Chrome and FireFox) I have not used to access the site before, and still no joy. I have tried both my phone and tablet, same thing. It keeps showing "The site can not be reached". I have cleared the cache of my default browser (Opera) as suggested, still no joy! Something weird is going on!