In most of the cases this is a conflict with permissions, so go to
admin/content/node-settings/rebuild and rebuild the permissions.
This happens when you test some access modules and they're not correctly uninstalled, also take notice that views not always uses the same permissions this is why you can see your node in views but not in
Also if you don't have any access module installed and the rebuild doesn't work, have a look in your database and execute the following queries:
TRUNCATE TABLE node_access;
INSERT INTO node_access VALUES (0, 0, 'all', 1, 0, 0);
This should also fix it.
You can try to install Devel and use the Devel Node Access module shiped with it on the node to analyze the problem.