Most current threats that affect computers come from the internet. If you don’t trust a specific program or an email attachment, doubt no more: Sandbox could be the application you've been looking for.
This tool creates a virtual space on your hard drive where files are stored. From here, you can open them without the fear of them changing your system configurations, installing worms or viruses...
This utility is great for just about anyone, even if you aren’t familiar with how to use the computer. It comes with a very complete and thorough configuration assistant that helps you install the program.
Virtual Sandbox can block the activity of 'iffy' programs, and it can also ask you before running an application.
Finally, the previous version, 1.0, is free and you can download it from here.