What parts of internet explorer does avast use?

I am interested in using Avast 4 in my soon to be upgraded system. I will be using Win98SE with 98lite. Win98SE has IE as part of the operating system but since I intend to use Mozilla firebird, 98lite installs Windows without most of IE (some pieces are left in for compatibility). Does Avast all of IE or just some of the components? If it does use some components, what are they? I would like to use Avast if it is possible, preferably without IE. Thanks.