WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.
Diskdeleter - Diskdeleter is data removal software that helps protect your privacy by securely deleting data from your hard drive.
TreeSize - TreeSize tells you where precious disk space has gone to.
DriveStrike - Remote Wipe on any operating system in one place using DriveStrike. Data Breach Protection for your laptop, smartphone, and tablet.
SpaceSniffer - SpaceSniffer is a freeWare (donations are welcome) and portable tool application that lets you understand how folders and files are structured on your disks.
Wiperapp - Software build to meet all needs of companies dealing with erasing data on daily basis.