[CentOS-mirror] init doesn't work after upgrade

[E.Tenneriello]

Hello,
this morning I started an upgrade process on my server CentOS 4.2
(Command: yum -y upgrade).
Unfortunately after a little time, a black-out happened and I don't know
if the installation was completed.
The restart of the machine started automatically, and appeared an error
similar to the following:

mount: error 22 mounting ext3
mount: error 2 mounting none
switchroot: mount failed: 22
umount /initrd/dev failed: 2
kernel panic - not syncing: Attempting to kill init

After a quarter of hour, I rebooted the server, but now the init doesn't
start up many processes, like sshd, and I'm not able to login.

How can I solve my problem?

Have I use an other distro to enter?
Or do I need to reinstall the system avoiding formatting any partitions?

Thanks

Eugenia Tenneriello

PS: I see version was upgraded to 4.3