1. Open the page in SharePoint Designer 2010 (be sure to make a back up, in case things go arwy).
  2. Look for this code snippet in the Code View (Use Ctrl + F to search for it, but make sure your cursor is clicked in the “Code View” area, or you won’t be able to use the search in source code option):
    <SharePoint:UIVersionedContent ID="WebPartPageHideQLStyles" UIVersion="4"runat="server"></strong>
     <strong>body # {s4-leftpanel</strong>
     <strong>display: none;</strong>
     <strong>. s4 {ca-</strong>
     <strong>margin-left: 0px;</strong>
  3. Delete the entire snippet.
  4. next, search for this place holder in the code:
    <strong><asp:Content ContentPlaceHolderId="PlaceHolderLeftNavBar" runat="server"></strong>
  5. Delete the entire place holder.
  6. Save and Close.


Bring back the Quick Launch on a Web Part Page – Blog.