Use a bootable CD or take the drive out and hook it up to another computer.
Bootables I'd recommend:
Parted Magic -
www.partedmagic.com (Click the 'Mount' tool on desktop to mount your HDD, a filemanager will open automatically)
Ultimate Boot CD 5:
www.myubcd.com (you will need to start a DOS tool that offers Ntfs support)
Bart PE:
www.nu2.nu/pebuilder/ I do not recommend Knoppix for tasks like this because it comes with a hidden root/admin account that may cause permission issues. It's easier with Parted Magic which is made to be a recovery OS.