Check this link for how to setup your /etc/hosts file. It must have been deleted by accident.
I get the following error message when booting;
Could not lookup internet address for localhost.localdomain. This will prevent GNOME from operating correctly. It may be possible to correct the problem by adding localhost.localdomain to the file /etc/hosts.
There is no such file /etc/hosts
You should arrange it like this:
[root@xxxx root]# vi /etc/hosts
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 abcd localhost.localdomain localhost
x.x.x.x abcd abcd.com mail www (if you have a domain)