I have a Windows XP system that i am trying to copy the ntldr file back to the system so that it will boot, i am using Knoppix Live CD.

When Knoppix loads, I see the HDD on the desktop When i double click it I get -

Could Not Mount Device. The reported error was mount: I could not determine the filesystem type, and none was specified

fdisk -l shows:

/dev/sda1 * 2 30393 244123740 44 Unknown

I run:

mount -t ntfs -o user,umask=0222,nls=utf8 /dev/sda1 /mnt/windows

and get the error

Bootsector checksum failed
Failed to startup volume: Invalid Argument
Failed to mount ' /dev/sda1': Invalid Argument
The device '/dev/sda1' doesnt have a valid ntfs
Maybe you selected the wrong device? Or the whole disk instead of a partition (e.g. /dev/hda, not /dev/hda1)? Or the other way around?

This is a mission critical PC and really need to get it back up and going. Any help would be greatly appreciated!