rhel is very often installed to a headless server and has no need for any gui
you need to install the desktop environment
please consult the rhel documentation for the CURRENT, RHEL 6.3 .
https://access.redhat.com/knowledge/...erprise_Linux/
with Red Hat your first stop is the redhat knowledge base
almost all and every normal everyday question has a answer there
https://access.redhat.com/search/quick?
( you will need to login to redhat with the credentials you set up when you bought the
required support contract / license )
Also on a VM
it might be your VM settings that are causing problems