WinCDEmu is an open-source CD/DVD/BD emulator – a tool that allows you to mount optical disc images by simply clicking on them in Windows Explorer. If you have downloaded an ISO image and want to use it without burning it to a blank disc, WinCDEmu is the easiest way to do it.
Free Software
Sandboxie
Sandboxie runs your programs in an isolated space which prevents them from making permanent changes to other programs and data in your computer.
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. By using a Treemap visualization layout, you have immediate perception of where big folders and files are placed on your devices. Treemap concept was invented by Prof. Ben Shneiderman, who kindly permitted the use of his concept into this tool.