The first is called Sandboxie. Its name accurately describes what it does: it creates a sandbox environment on your PC within which you can browse safely.
The strange name "sandbox" derives from the Java world where it refers to the highly contained and restricted environment in which Java programs (applets) are allowed to run. They are allowed to "play in the sandbox" but not go outside it. The important point is that while running in the sandbox, the programs have no access to your PC.
So it is with Sandboxie. While browsing within the environment provided by Sandboxie you are totally corralled off from your other parts of your PC. Any files you download are isolated to the sandbox. Similarly, any programs that are executed only do so within the sandbox and have no access to your normal files, the Windows operating system or indeed any other part of your PC.
http://windowssecrets.com/reviews/1-Sec ... ity-part-3