The easiest way to tell if a site still exists is to ask another Internet user to go to the site and see what happens. If the other user cannot access the website either, there is nothing you can do but wait to see if the site comes back online at a later date. If the other user can access the site, odds are you have a corrupted cache. Web broswers cache the pages you access. This makes frequently accessed pages faster to download.
Problems can occur when the cached files become corrupted.
Fortunately, this problem has a simple fix - purge the cache. This will expand the available options. Click on Cache. Click on the Advanced tab. Click on the Settings button.