I have Knoppix installed on an external USB drive. Also had it installed on a USB flash but later removed most files, but the
syslinux file is still there. As with others, my internal Windows HD is not accessable when I boot Knoppix from the
external USB HD. I tried to mount the HD, as per the instructions posted her, but to no avail.

However, I found a trick that seems to work for me. After booting from the USB drive, I then install the USB KEY that has the
syslinux file. After it is mounted, I perform an fdisk-l to see all the disk devices. Then I unmount the USB KEY and 99% of
the time the internal hard drive (Windows) is now mounted and usable. Why? I have no idea. I am a real
newbie to Linux.

As the man says, DO NOT WRITE to the NTFS disk. You will probably make is unusable in Windows.