Kat, I believe a lot worms are scripts. Won't do anything about the .vbs, .bat, .exe, .pif and and .scr files, but they shouldn't activate automatically and hopefully people don't open them on purpose.

There are probably a load of people around here who know more than me and can explain better. A script is a bunch of commands that make your computer do something, and can be included in HTML. And example would be those cute images that follow your cursor around on some web pages. Here's a page where the cursor does that.