You also might try checking from a different remote location, using other computers on the Internet if you cannot easily get yourself connected on another ISP.

You can check from several other geographic locations this way at the same time.

You can test yourself at the following URL:

SiteUptime - Website Monitoring Service

This will tell you that other locations can see the server fine, (or not fine) as well.

You should also be able to see your site as well using a web based proxy like proxify.com, or any of the other web based proxy sites like the ones you see at CyberSyndrome : Web-based Proxy

Also, if you have not seen this page on our site:

Web Site Diagnostics and Troubleshooting

It too contains some useful information for diagnosing connectivity issues.

Let us know what you find.