If it's chrome, click the wrench icon, highlight bookmarks and select show favorites bar.
If it's ie9, right-click the star icon and check favorites bar
If it's an older browser, i would have to connect to an older pc to confirm
Click the wrench (right upper corner)>> tools >> always show bookmarks bar
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In the latest beta versions.
Click the wrench (right upper corner)>> Bookmarks >> show bookmarks bar
If you are using IE9 and your favorites bar in IE intermittently disappears then it is a common issue a lot of people are compalining about and unfortunately it hasn't been fixed yet.
try this, when your favorites bar is missing try minimizing the explorer window and then restoring the window. This usually works. very annoying