Disk Space Fan Pro 

Disk Space Fan Pro is a drive space diagnostic tool. It scans your hard drives and displays information about them allowing you to assess your space usage. It is ideal for finding duplicate files and large files that you might not need and are not aware of.

The main window shows all your hard drives, with very basic information about the space usage on them. It shows the capacity of the drives, the space used, and the space free. If you scan the drives, Disk Space Fan Pro will return much more detailed information. The next graphic that is shown is a much more detailed and useful one. It shows a graphical representation of all the big files and folders on your drive. Those that are bigger are located closer to the centre and are larger in size. If you move your mouse over them, you will see what the file or folder is named and the hard drive space it is occupying.

Disk Space Fan Pro will automatically look for duplicate files, and if you want to browse them it will even show file names, sizes, dates of modification and creation, and you can then delete them.

There are two versions of this program. The Free one is more basic than this one, but it is still useful for determining what your space is occupied with..