[ubuntu] cant find main menu bar on desktop

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http://ubuntuforums.org – i recently installed ubuntu 12.04.... but i cant see the menu bar Applications, Places, Systems at top left of my desktop,, instead even when i have minimized everything i see the menu items File, Edit, View etc which are folder options etc things,,, although on right top corner i can see icons of bty, speaker, time, etc.... wts the isue,,,do i need to do something special to bring it,,,should it not b there by defaul (Hardware)