My Laptop can’t run Redhat 5/Cent OS 5!!!

When I install Redhat Linux 5 or Cent OS 5 on my laptop, it installs perfectly but when it reboots & starts then its only show non GUI mode.
I mean no graphical interface. It shows ‘no X Windows server’.
My laptop is HP Probook 4430s.
Can you help me, thanks?
