Cannot Mount Hard Disk

I have a Dell C400 that normally boots and runs Windows 2000 SP4. the BIOS shows a 20G HD listed as the hard disk. It no longer boots to windows, and only presents a blank black screen instead of the normal W2K boot screen, I booted off the Knoppix 4 CD, and the HD shows up as HDA1. When I click on the drive to try and salvage the data, I receive the message "could not mount device, the reported error was: mount: wrong fs type, bad option, bad superblock on /dev/hda1, missing codepage or other error".

Being a Knoppix newbie, I'm not sure how to try and repair the disk from Linux, or if the drive itself is physically damaged or in need of a complete format. Any assistance would be appreciated.