Firefox reset itself? I lost all my bookmarks.

I clicked in to firefox like i did 30 some other times today but the last time i went into it 2 new pages came up,

Thank you for installing google tool bar and something about pagerank.
and my homepage was changed,and bookmarks are gone.

I did a system restore for earlyier in the day and it did not fix anything.

I dont no what to do it looks like im screwed.

 

not much you can do there.should've saved it or transfer it