WinDirStat (short for Windows Directory Statistics) is a “disk usage viewer” that can help you visualize your used hard drive space. This allows you to track down which directories and file types are taking up the most space. Also, it’s a fun thing to see! You can download it here. WinDirStat runs on “all current variants” of Windows.
As seen in the image below, in the upper-right window, flac files are taking up the most space (compared to all other file types) on my hard drive.
After you run WinDirStat, you will be presented with an option between showing all your drives, individual drives, or even a folder. After you select a drive it begins scanning. This may take a few minutes, but you get a nice pac-man looking animation by your folders.
There is a lot you can do inside WinDirStat. You can browse through all of your folders and the files will be outlined in the visualization. Moving your mouse over a block in the visualization will display the file’s path and name in the lower left corner, and you can even delete files right in WinDirStat!
This application is mainly just for fun, but it can also be useful for tracking down big files. Just make sure not to delete any important files!