平時開contact list果版係個名下面會有d tabs~~揀email~~sharing folders etc~~但係唔見左幾個tabs~~~

咁可以點算~~~

This situation sounds strange, at least I didn't experience before ...
Anyway, I am not sure if the following can help you, because it'll just restore the default setting on the tabs, may or may not restore the "menu bar" that you mention.  Hope it works on you.

from the MSN, click the following:
Tools -> Options -> Tabs (left-hand-side) -> Restore Default (on right-hand-side)