I recommend starting with a text editor and a browser. May I recommend Sublime Text and Google Chrome. Then, you will want to learn HTML + CSS. After you are comfortable with html and css, move on to Javascript... Before using a website hosting company, test your site locally with an AMP local development server.
No, they created Google Now which overlapped with this product. Google is constantly starting new projects and ending ones that either conflict with new ones or become obsolete.
Except that Google Now is not for desktops or a 'start page' (at least not yet), and perhaps more importantly, is not accessible or extensible by developers, or customizable by users.
I do think you have something there about desktop use. What's important here is that Google adapted to the migration of users to mobile devices. Just like desktop PCs are in decline, so are apps that are desktop-only.
I'm running Win 7. I was also served malware while listening to music on grooveshark. Had to restart my computer afterwards. I think it has something to do with their ads.