I checked your site. The first time, the site loaded with posts. The second time, the theme loaded and in the content area, this appeared.
Not Found
Sorry, but you are looking for something that isn’t here.
If you search your theme’s “index.php” file, I think you’ll find the “Sorry, but you…” line at the bottom after an “else” statement.
So, it appears that your WP install is (1) connecting to your database properly; (2) loading the basic information [site address, name, theme]; (3) but not any posts or comments.
This is stretching my expertise, but here goes… I think that your WP database could be damaged.
First, backup your WP database: Backing Up Your Database and, if you can export your posts via the Admin interface, then do that, too.
Second, switch to a default theme. If the problem persists, then this isn’t a problem with your theme.
Third, try the instructions here – Repairing (WordPress) Database Tables. Then, empty your browser cache and try your site again.
If that doesn’t work, redo your WP install – new database and so forth. Then restore your database (instructions are linked in the backing up page I linked to earlier).
If you’re still having problems, then this could be a server issue.