I somehow don't think assembly is going to help you as an end-user in combatting viruses, unless you really enjoy pain. I mean really. Doing something like reprogramming the virus in reverse in assembly isn't very trivial.

Your better bet is to use backups, a hex editor, and a good knowledge of what the infected file *should* look like.

If it's just a word document, you can grab a ton of the text right out of it and redo the formatting, for instance. If an executable, you're probably screwed without backups or a virus which has merely appended/prepended/inserted itself without overwriting anything.