If you haven't yet resolved your problem with missing bookmarks: here's how I fixed that problem.
Uninstall the new version. Then open Task Manager to make sure no other firefox processes are running. Restart, then reinstall v 2.0.
All my bookmarks reappeared and I could use tabs again. I hope this helps.
;). And I should have kept reading the thread... I found someone post a fix later. Glad to see they figured it out! I had to guess, but operated like I always do when a normal install on some program makes my pc wacky.
Right now, I'm trying to determine if my periodic cursor freezes on the other computer are related to the v 2.0 install. The bookmark problems happened on that pc as well, not this one, but I've already done the uninstall/reinstall thing so am unsure if I need to just go back to the older 1.5 version on that one.
Question for you: do you have linux and windows on the same pc, or are you talking about 2 different machines?