The first thing to note is that your mount point is /c

mount -t ntfs -o rw /dev/hda1 /c


You should therefore just list /c
i.e.

ls /c

this will give you all drive contents then you can do
cd /c/Windows

However why not open your home folder and in the location bar type /c this why you
have a graphical why to manipulate your files without having to type upper or lower
case names.

For permanent mounting create an entry in /etc/fstab
Example

/dev/hda1 ntfs-3g /mnt/winxp defaults,noauto,users 0 0

uses the ntfs-3g library with write capability to mount your windows NTFS partition.
It is not mounted at boot (noauto) but can be mounted simply by using kwikdisk
(if you use KDE)
HTH