The NTFS file system provides built-in security controls in Windows NT, 2000, XP, Vista, 2003, 7 and 2008. An NTFS-secured hard drive will appear locked in another system. You can't access the drive because the NTFS permissions are set up for users that don't exist on your system. The only way to correct this problem is by taking ownership of the hard drive. To take ownership of a hard drive or partition, you must be an administrator.
Open "My Computer."
Right-click the hard drive or partition you want to unlock and click "Properties."
Change to the "Security" tab and click the "Advanced" button.
Change to the "Owner" tab and click "Edit." Windows Vista and 7 users click "Continue" in the User Account Control window.
Click your user name in the user list.
Click the "Replace owner on subcontainers and objects" check box.
Click the "OK" button twice.
Select the "Edit" button to add access permissions for your user. Windows Vista and 7 users click "Continue" in the User Account Control window.
Click "Add," "Advanced" and "Find Now."
Click your user name in the list at the bottom of the window. For external drives that you want accessible on other computers, also click "Everyone."
Click your user name and then click the "Allow" check box for "Full Control." For external drives, do the same for the "Everyone" group.
Click "OK," "Yes" and "OK" again. The drive is now unlocked.
You can take ownership of a locked folder or file using the same method.