Not sure if your web server runs under linux, but if it is the case, then you should check for directory
/etc/httpd/conf.d/
(CentOS/RHEL) or
/etc/apache/conf.d/
(Debian/Ubuntu).
There you should find Apache's configuration files, one should be dedicated to your web site. In there you should find the directives regarding web server name and other settings.
Without any contextual information, it's quite hard to tell you more about this.
Good luck. Hope this helps.
[EDIT]
To try to find Apache's base configuration file, type:
sudo find / -name httpd.conf
Once you located this file, open it with
vim
, and search for a
ServerName
and/or a
NameVirtualHost
directive; this should be the root web server address.
That is just the beginning of a track, though, as Apache's configuration files can come in so many different flavours :)