Booting straight up to GRUB is not the default boot method for CentOS 5 & 6.

This How-To was written to show you step by step the process of resetting the root password on your CentOS 5/6 installation.
Steps (7 total)

1. Boot or Reboot your CentOS installation

From the console ATL+CTRL+DEL will get you headed in the right direction.
2. Press Any Key

After the installation reboots, it will...