I would guess that you got partition table corruption.
You may want to try to fdisk /dev/hdc in the way it was partitioned before.
However, boundaries of partitions are to known presizely for that, though.
You may also try gpart(8). It does not look at partition table and may find
partition boundaries.
Reinstalled Suse 10.1 from scratch. Went very smooth. Running
again...just curious for how long.
Another question however: is ReiserFS capable of handling sudden
reboots? I suspect my systemboard needs to be replaced since it reboot
or freezes now and then, but so far I never had an fs being ruined
beyond repair.