Boot sequence freeze : mounting /


I recently reboot a poweredge 400 sc on freebsd 7.0.
During the boot, the system told me "/" was uncorrectly unmount.
Next the boot sequence mount a partition (/) and freeze. The system doesnt respond anymore.

I try to boot in all mode (sage, without acpi, ...) and same thing. Freeze and freeze again a the same time.

Nothing wrong in the dmesg. Disk are raid 1 and physically operationnal.

Any help ?
Well, it seems something got seriously damaged. I'd suggest to try to fsck from a fixit shell (running off a CD).