Centos won't boot on T110 II

On a T110 II with dual hdd i have disabled RAID  mode in BIOS and set it to AHCI sata mode.

I have installed Centos and make my on RAID using build in Centos Raid Software. I have created two partitions "/" and "swap" and the installer went fine, but after reboot Centos won't boot, i get only a blank screen with a "_" blink and it is hanging up forever.

Grub was loaded on primary raid partion "/".

Centos is 5.7 x86_64

What is the problem?

Thank you