localhost.localdomain

[Antoniak Adam]

Hi guys,

I'm rather new to Linux and especially to networking. I got a bandwidth connection recently. It is provided by my cable TV operator and works out of the box. I didn't need to configure anything for Fedora. Unfortunately when I reinstalled my Fedora system, instead of localhost.localdomain in the bottom right corner of my log-in screen I have user32.supernet.pl. What is worse, while logging in, the error message appears informing, that the system does not have an e-mail address for user32 and Gnome may not work inappropriately. I'm asked to adjust /etc/host but have no clue what to include in it. Gnome actually works, but this error message is really getting on my nerves. 
How can I restore settings back to default without loosing network access?
Any help would be appreciated. Sorry if it is a silly question.

ADAM