TreeSize Free
Every hard disk is too small if you just wait long enough. TreeSize Free tells you where precious space has gone to. TreeSize Free can be started from the context menu of a folder or drive and shows you the size of this folder, including its subfolders. ... The space, which is wasted by the file system can be displayed and the results can be printed in a report. ... Each folder can be expanded in Explorer-like style to see the size of its subfolders. ... Scanning is done in a thread, so you can already see results while TreeSize is working.
http://www.jam-software.com/freeware/TreeSizeSetup.exe - 687Kb - Download - Screenshot

R-Drive Image
R-Drive Image 3. 0 is a potent utility providing disk image files creation for backup or duplication purposes. A disk image file contains the exact, byte-by-byte copy of a hard drive, partition or logical disk and can be created with various compression levels on the fly without stopping Windows... If you need to restore only certain files from a disk image, you can connect that image as a virtual disk and copy those files directly from the disk image using Windows Explorer or any other file utility.
http://www.drive-image.com/downloads/rdi_en_3x.exe - 11Mb - Download - Screenshot

Crap Cleaner
Crap Cleaner is a system optimization and privacy tool. It removes unused files from your system - allowing Windows to run faster and freeing up valuable hard disk space. It also cleans traces of your online activities such as your Internet history. But the best part is that it's fast (normally...
http://ptsavers.5gigs.com/dl/crapcleanersetup.exe - 1Mb - Download

Wiperaser 2004
Wiperaser 2004 is a secure data deletion tool. Its primary goal is to wipe files, folders and registry entries in such a way that nobody can recover them. It works on FAT, FAT32, NTFS and NTFS5 volumes and supports three data wiping methods: the well known Gutmann method,the US Department of... Can wipe free space or destroy entire hard disk contents at low level (using Direct Disk Access). ... It seamlessly integrates into your Windows Shell through a handy menu item which is always available when you right-click on any wipable system object (including the Recycle Bin and the Free Space...
http://www.liveye.net/download/wiperaser_setup.exe - 5Mb - Download - Screenshot

Prosto Disk Cleaner
If you had never thought of yourself as of a space hog, cleaned your e-mail folders on a regular basis, moved pictures and files to DVD and deleted the copies from the hard disk, uninstalled the unnecessary programs as soon as they were no longer needed, and did other things to keep your PC... Have you still wondered why has the computer kept getting slower, and the free room kept shrinking day after day? ... Certainly, buying a faster computer is not an option! ... Have you tried to figure out how can that be stopped?
http://www.prostosoft.com/files/pdcsetup.zip - 957Kb - Download - Screenshot

ShredIt for Windows
Files can be recovered from your computer's recycle bin. Protect your privacy with this easy to use file shredder that shreds data so it can't be recovered. Whether you want to erase a hard drive or wipe a file, ShredIt for Windows is the computer privacy software for the job. ... It shreds files, folders, disk free space, hard drives and external hard drives. ... It comes with step-by-step instructions, built in safety features, government standards compliance and a configurable overwrite pattern.
ftp://ftp.mireth.com/shreditpc.zip - 728Kb - Download - Screenshot

ShredIt X
How secure is your trash? Files can be recovered from your computer's trash. Protect your privacy with this easy to use file shredder that shreds data so it can't be recovered. Whether you want to erase a hard drive or wipe a file, ShredIt for Mac OS X is the computer privacy software for the job. ... It shreds files, folders, disk free space, hard drives, and external hard drives. ... It comes with step-by-step instructions, built in safety features, government standards compliance and a configurable overwrite pattern.
ftp://ftp.mireth.com/shreditx.dmg.zip - 3Mb - Download - Screenshot

diskSpace Explorer Network Edition
diskSpace Explorer 3 Network Edition is designed to help the networking administrator to allocate and manage the computer or server hard disk space the way professionals do. It features an intuitive pie chart that graphically displays the contents of your folders. ... diskSpace Explorer 3 can gain free space by compressing folders, by reducing the wasted space or by deleting the folders you no longer need. ... diskSpace Explorer 3 reports detailed information about the amount of space used and wasted by your files and folders.
http://www.innovatools.com/download/spexNetTrial.exe - 1Mb - Download - Screenshot

ShredIt
Files can be recovered from your computer. Protect your privacy with this easy to use file shredder that shreds data so it can't be recovered. Whether you want to erase a hard drive before disposal or wipe a file, ShredIt for Mac OS 8 and OS 9 is the computer privacy software for the job. ... It shreds files, folders, disk free space, hard drives, and external hard drives. ... It comes with step-by-step instructions, built in safety features, government standards compliance and a configurable overwrite pattern.
ftp://ftp.mireth.com/ShredIt.FAT.sit.hqx.zip - 2Mb - Download - Screenshot

Data Nuker
When you delete a file from Windows it just mark the file as deleted in file allocation table, but the data of the file is still on your hard disk, Windows does not physically remove deleted files from your hard disk. Emptying your Recycle Bin does NOT protect you at all. ... Shreds disk free space so you can even use shredder to destroy previously deleted files on your hard drive. ... Your sensitive files can be recovered, even after you format your hard disk! ... Completely remove sensitive data from your hard drive by overwriting it several times with carefully selected patterns.
Http://malwareremover.com/download/mrdn/mrdn2000.exe - 3Mb - Download - Screenshot