First check if you have really the Advanced toolbar active and not the Basic toolbar. Click with the secondary (right) mouse button anywhere on an existing toolbar and select from the popup menu Advanced to switch to the Advanced toolbar.
If you already use the Advanced toolbar, click with the secondary (right) mouse button anywhere on an existing toolbar and select Customize Toolbar. Look in the left area if the HTML Toolbar is still present in your toolbar configuration file. If it is not present anymore in the left area, you have deleted it by mistake.
If you can see at View - Views/Lists - Toolbars only Main ToolBar and not also HTML ToolBar and TOOLS ToolBar, you have deleted the additional toolbars from your toolbar configuration file Advanced.tfg.
If you really have deleted the additional toolbars from the Advanced toobar configuration file, use Manage Toolbar Configurations, select the Advanced toolbar and press the Reset button to restore the defaults.
Best regards from Austria