hola que tal amigos yo otra vez disculpen si los molesto pero gracias a ustedes encontre soluciones
miren este es mi problema
al sacar mi disco duro IDE de la pc y colocarlo como HD Externo(USB)
quiero arracar el CentOS pero me muestra un error

mount: could not find filesystem '/dev/root'
Setting up other filesystems
Setting up new root fs
setuproot: moving /dev failed: No such file or directory
no fstab.sys mounting internal defaults
setuproot: error mounting /proc: No such file or directory
setuproot: error mounting /sys: No such file or directory
Switching to new root and running init
umounting old /dev
umounting old /proc
umounting old /sys
switchroot: mount failed: No such file or directory
Kernel panic - not syncing: Attempted to kill init!