F15 boot problems

[Robert M. Albrecht]

Hi,

Fedora 14 is running on the machine.

I tried both F15 Beta and F15 Test Compose on this machine.

The system is booting from cdrom, but does not even get to grub. 
Directly after booting there is only a blinking cursor on an empty text 
mode screen.

Creating an usb stick (unetbootin on Mac OSX) does produce a booting system.

How to troubleshoot a bootloader problem ?

cu romal