eww.. that doesn't sound fun.
The first thing I would do is boot with a utility CD (ubuntu live, knoppix live) and either badblocks with a rw test, or fsck -cc the root filesystem.
My questions.. (forgive me if they sound like "duh, I checked that")
IDE bios settings.. make sure it's not fixed set to the wrong drive size, or auto-detecting the wrong drive geometry.. (LBA? whatever)
Is there anything on the IDE chain that could be causing issues. CD-ROM set to slave, but master doesn't like having slave drives without a "single->master" jumper
FSCK! did you try badblocks? badblocks with RW test? fsck -cc?
What brand of IDE drive is this?
_________________________
80gig red mk2 -- 080000125
(No, I don't actually hate Alan Cox)