How do you set Avast to virus check during boot?

I was looking for a way to set Avast to run a virus check before the OS boots. Is it possible? I went to the Help menu every which way but loose, but came up with nothing. Was I looking in the wrong spot? Any help would be appreciated. Thanks!

Oh, and I’m using Windows XP Pro, SP2, fully patched. And it’s Avast version 4.7.

See this thread:

http://forum.avast.com/index.php?topic=19407.msg163565#msg163565