You seem to have a liking for running old versions of programs or you don't bother to update your signature.
We are currently on avast version 7.0.1466 (just released very recently), your signature indicates version 5.0.
Firefox is on version 14.0.1 your signature indicates version Firefox3.6.13.
I'm not entirely sure what you want to always run sandboxed as you don't say ?
But in the latest versions of avast Pro/Internet Security suite, you can elect to have a particular application always run sandboxed.
To run an application or to browse the web using the sandbox, just click on "Run a virtualized process" then browse the files on your computer to find the required application e.g. Internet Explorer. The browser or other application will then open in a special window with a red border, indicating that it is being run inside the sandbox.
In the Expert Settings, you can further define applications that should always be run in virtualized mode, and trusted applications that should never be virtualized.
