To defragment a file all you have to do is drag and drop it into the program's interface. WinContig will detect the files it can defragment and the ones it can't. Files that have been written contiguous in the disk will not be moved.
The defragmentation engine used by WinContig is the same as Windows'. The program doesn't need installing and doesn't modify the system's registry, allowing you to use it from a removable device with no problems at all.
By default, the program's language is set to English, but you can access 'Options' in the 'Language' menu to change it to Spanish.
Improvement in defragmentation priorities. Fixes some compatibility problems.