It may be a BIOS configuration issue, as i discovered using the command below, in text mode
Code:
startx -- -verbose 5 -logverbose 5
and then looked up into /var/log/messages.
[plug&play OS] needed to be set to NO
[Assign IRQ to VGA] needed to be set to YES.
I did that and it worked, so i suggest Mortimer to check that out.
[motherboard: ECS K7S5A]