Kernel panic – not syncing: VFS: Unable to mount root fs on known-block(0,0)

Kernel panic - not syncing: VFS: Unable to mount root fs on known-block(0,0)

assuming your GRUB (/boot/grub/grub.conf) have something like this:

# grep -E "^hiddenmenu|^timeout" /boot/grub/grub.conf
timeout=0
hiddenmenu
#

Try holding “Ctrl” at GRUB splash/menu screen and then select previously working kernel. If that won’t help then boot into a rescue mode and do following:

# yum remove kernel-VERSION
# yum update kernel

reboot your system and you _SHOULD_ be OK)