I've installed CentOS 7 as a virtual machine using virtualbox. That part worked fine and I've got my network connection working properly. I've updated yum and that worked fine.
It would seem that all is well but there's a problem in that I cannot install Gnome Desktop. When I run sudo yum groupinstall "GNOME Desktop" I get back:
"Maybe run: yum groups mark install (see man yum) No packages in any requested group available to install or update"
I've run repolist, grouplist and opened the .repo file and all 'appear' to be correct but I cannot install anything via yum.
How do I fix this?