@Sarincv, Don't login as root. That's a very bad practise!! It's also very dangerous.
Just login as a normal user in Mandriva Linux. Open the Terminal Window & type:
$ su -
(Enter root password)
Now you are logged in as root.
# cd <directory path>
To delete a file use the 'rm' command
# cd /mnt/win_d
# rm filename
Once your job is done logout as root,
# exit
WARNING : Use 'root' login with a lot of caution!! Deleting a System file used by the O.S can wreck havoc!!