Sandboxie is an incredible little, lightweight program that allows you to run an application sandboxed which means anything the sandboxed app would normally write to disk is instead written to transient storage which can be easily removed.
From the Sandboxie site
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.
This works great when installing new applications that you aren’t sure you are going to keep. I needed to do some testing with several video ripping apps and installed each of them sandboxed. I tested four separate apps and decided to keep one. When I was done testing I simply deleted the sandboxes and reinstalled the app I liked using the normal process. This meant I didn’t have to worry about malware or dirty uninstalls leaving files on the disk or registry entries. Awesome.
As the excerpt above indicates you can also run apps you have already installed in a sandbox. This is particularly helpful when browsing the internet as any files typically written to your cache will be written to the sandbox instead. Want to try a new browser toolbar but don’t want to commit to it? Install the toolbar while the browser is sandboxed.
While reading through the Sandboxie forum one individual commented that they had installed Sandboxie in a Terminal Server environment sandboxing the browser. Prior to installing sandbox their AV/malware scanners were picking up 200-400 malicious attempts a week. Sandboxie reportedly reduced the number of malicious attempts to 6 and those were done outside the sandbox. Incredibly impressive.
There really isn’t any reason you shouldn’t install Sandboxie. Go get it now.