I'm using Firefox 4. I have already created a Sync account from one PC. Now, it just so happens that I'll be getting rid of this PC soon, and therefore another PC should become my main device. So I have two questions: 1. How do I make this second PC my main device, so I can add other devices on it directly (without choosing "I'm not near my main device," etc.)? 2. Somewhat different topic: I haven't yet actually synced a second device. I'd like to know, what happens to any bookmarks that are already present on my second PC when I sync it with the bookmarks on my Sync account?