Unable to install RHEL-5 in SATA 2 hdd

Hi,
I am trying from last 2 weeks to install rhel-5 in sata 2 hdd but i am failed to install it properly.
But i can install Fedora7 and 8 perfectly .I don't know why this is happening in RHEL-5.
The problem is that the system is not able to detect my SATA 2 hdd.
i aslo tried with the below procedure
in boot prompt
boot: linux all-generic-ide noapic nolapic
after that the machine will install and u edit the grub.conf file
kernel /vmlinuz........ all-genric-ide
but still its not detecting the hdd

my pc configuration is(core2duo,2.66ghz,1gb,800fsb Ram,160gb SATA 2 HDD-Hitachi)

your replies will be highly appreciated
waiting for the replies.

if you added the noapic & nolapic to the boot command line, why not also add it do the bootloader?