DirSize will show you where. Download 2 Clean Disk is a user-friendly utility designed to free up disk space by deleting temporary directories and other files such as leftover, unneeded setup files. Designed not to interfere with Windows or any another program. Once a month, with the click of a button, you can run it to update your version of Clean Disk to the latest available. This version features some minor bug fixes, improved menu links, and some other, minor changes to the interface.
Application is very simple.
We select the CD-ROM drive in which is the CD we want to check. Application then checks the drive, displaying status. When done, all errors are reported. Every harddisk is too small if you just wait long enough. Treesize tells you where your precious Clusters have gone to.