DirSize is a simple, easy-to-use and small application that will scan your hard drive(s) and display them in a simplified tree with the disk usage for that tree.
This allows you to quickly and easily see what folders on your disk contain large amounts of data.
Use - Run DirSize and it will begin to scan all local drives. You can browse the returned tree, or change the scale of the data size at the bottom.
Click "Refresh" to rescan the drives. If you find a folder and you want to take a closer look at the files, simple right-click on the folder and select "Open in Explorer."