Solution: Your boot partition is on a disk using the GPT partitioning schem

The solution or fix for error
"Your boot partition is on a disk using the GPT partitioning scheme but this machine cannot boot using GPT"
while trying to install cent os 5.6 on Hard Disk with 2TB or larger space.

Solution 1:
Try installing Cent OS 6 and then try to reinstall Cent OS 5.6

Solution 2:
- Go to rescue mode
- Change the GPT to MBR using parted command

parted /dev/sda
mklabel msdos
quit 

- Reboot