Sandboxie is a small program that lets you run any application in a sandbox. When you run a program on your computer, data flows from the hard disk to the program via read operations. The data is then processed and displayed, and finally flows back from the progam to the hard disk via write operations. Sandboxie makes the software write back to a sandbox, a temporary storage area instead of the normal location on the host PC. It is something like running any software inside Virtual PC or VMWare. Doing any change inside the Virtualized environment does not affectthe base or host computer. Sandboxie weighs around 200 KB and is a freeware.