[CentOS] Unable to edit resolv.conf

>>> I changed ISPs and need to update name servers in resolv.conf.
>>> 
>>> I have tried nano, gedit, Webmin, system-config-network and it won't allow
>>> me to make the changes.

Have you tried adding PEERDNS=no to your ifcfg-device file? If that 
doesn't work, you might be able to use NM_CONTROLLED=no as well.

Barry