When you want to rename you’re MOSS or WSS Server follow the steps on the following site:
http://www.sharepointblogs.com/mirjam/archive/2007/08/06/renaming-a-moss-server.aspx
But if you’re like me and renamed you’re server before you red that blog post. You’re SharePoint 3.0 Central Administration link will not work, DNS errors.
In mine case it was because I had some old alternate access mappings with the old servername in it,
but I could not change the mappings, because I could not get the Central Administration page loaded, without DNS errors.
To solve this problem I edited the HOST file in C:\Windows\System32\drivers\etc and added 127.0.0.1 <OLDSERVERNAME>
After a ipconfig /flushdns and ipconfig /registerdns the central administration page was accesible.
After changing the alternate access mappings to the new server name, the original HOST file could be restored