maybe some Internet Explorer browser setting is messed up and files of type .zip are automatically opened with notepad?

Maybe download Firefox (that is the browser I am using in the screen shots above).

If you google the phrase File assocation fixes for windows vista you will find a number of web sites that talk about this problem. So you are not alone. The top one on the list, winhelponline.com, has a solution for most common file types including .zip. they fix the problem by changing things in the registry.

although this would probably fix your problem, when novices change things in the registry, I worry, because it is possible to make a computer unusable if done wrong.

do you know any computer experts you trust?

another good experiment to do would be to try to download a completely different zip file from a different web site that you trust. if you try to download a different zip file from some other website and it opens notepad and you see the odd symbols, that means it is probably the problem above where the file association for files of type .zip are set to open with notepad.