Sandboxie changes the rules such that write operations do not make it back to your hard disk.
The illustration shows the key component of Sandboxie: a transient storage area, or sandbox. Data flows in both directions between programs and the sandbox. During read operations, data may flow from the hard disk into the sandbox. But data never flows back from the sandbox into the hard disk.
If you run Freecell inside the Sandboxie environment, Sandboxie reads the statistics data from the hard disk into the sandbox, to satisfy the read requested by Freecell. When the game later writes the statistics, Sandboxie intercepts this operation and directs the data to the sandbox.
If you then run Freecell without the aid of Sandboxie, the read operation would bypass the sandbox altogether, and the statistics would be retrieved from the hard disk.
The transient nature of the sandbox makes it is easy to get rid of everything in it. If you were to throw away the sandbox, by deleting everything in it, the sandboxed statistics would be gone for good, as if they had never been there in the first place.

Sandboxie Main Feature:

• * Protecting your Freecell statistics
• * intercepts changes to both your files and registry settings, making it virtually impossible for any software to reach outside the sandbox.
• * traps cached browser items into the sandbox as a by-product of normal operation

Sandboxie Current Version:
Sandboxie 3.24

Sandboxie New Version Change Log:
This version improves the overall stability and usefulness of Sandboxie through various bug fixes and enhanced functionality:

• * Improved compatibility with Windows Vista Service Pack 1.
• * Support for blocking Internet access to more than one sandboxed program at a time.
• * Support for the new bookmarks system introduced in Firefox 3.
• * Removed domain restrictions: Sandboxie can again be used in a domain network without additional license keys.
• * Some performance improvements and security enhancements.
• * Translation to Korean, contributed by doa.
• * Resolved conflicts with third-party software: AVG 8, Ad Muncher, Novell NetIdentity, Trend Micro Internet Security 2008