Is there a working OS on this laptop?
Try to download and boot a linux live-cd. I would suggest you try KNOPPIX. If the live-cd boots and finds the HDD, you can use commands, including lsmod" to see how it mounts and is configured by linux.
If the live-cd does not boot with the HDD, try the chestcodes. Perhaps there is a problem with the SATA modules, perhaps the BIOS doesn't care for linux.
Some Dell laptops require "noscsi" or nowhatever it is that they stall at when attempting to boot and function.
As the previous post suggests, the if the BIOS is set to AHCI, CentOS may want a driver for the SATA HDD before it recognizes the HDD as a device.