You've posted in the incorrect section and you've given no information about what or where you've lost icons from, If you are going to post questions then please think about the question before you post it and try and include relevant details as we are not mind readers!
Now if you want help try again and state what exactly the problem is and more importantly , what exactly it's effecting.
(though the answer will probably be click the view menu > toolbars and select the relevant toolbars to be displayed)