( the option to "resize" is grey out / disabled )
This could be because "ntfsprogs" is not installed.
In GParted try : GParted > Show Features
Under "NTFS" if it does not list the ability to "shrink" this is probably the problem.
Install ntfsprogs with the command: sudo apt-get install ntfsprogs
Restart GParted, resizing should be available now.
Reference - Gparted won't shrink NTFS [ http://www.techsupportforum.com/alternative-computing/linux-support/335974-gparted-won-t-strink-ntfs-2.html ]
