How should I build a basic website, which files do I need usually?

index.html
about_us.html
products-services.html
term_of_service.html
contact.html

favicon.ico
robots.txt
style.css
javascript.js

images/logo.gif

How can I create a pure css tree-menu without any javascript/dhtml etc? It must be cross-browser including Google Chrome.

How can I build html-areas with rounded corners?

After I have installed some modules and activated them, admin-menus-navigation-edit gives page not found error. Any idea?

Importing interface translations

Error importing interface translations
Please continue to the error page
An HTTP error 404 occurred. /batch?id=10&op=do

This happens when I try to add a language. There is no problem if I try it with Internet Explorer. I am using Drupal 6.9 and Firefox 3.0.6.

Any idea?

Does anybody know why windows xp speaker icon disappearing? You can disable/enable from system setting to bring it back, it happens again later.