Can`t mount external hdd

I am using Debian and I`m using Windows as well (much longer).

I loaded a external disk on Windows but when trying to mount on linux again I keep getting the same error:

Error mounting: mount exited with exit code 1: helper failed with: Unprivileged user can not mount NTFS block devices using the external FUSE library. Either mount the volume as root, or rebuild NTFS-3G with integrated FUSE support and make it setuid root. Please see more information at http://tuxera.com/community/ntfs-3g-faq/#unprivileged

Tried mounting with command line but got another error:

:~$ sudo mount -t ntfs /dev/sda1 /media Mount is denied because the NTFS volume is already exclusively opened. The volume may be already mounted, or another software may use it which could be identified for example by the help of the 'fuser' command.

A little help would be much appreciated since all my files are on that hdd?