In version 2006, right click on any icon on one of the visible toolbars. A list of toolbars should pop up with check marks next to the ones that are currently visible. The ones that aren't checked are off. While that list is still up, left click next to the layers toolbar.
If it is a version prior to 2006, then the toolbar is called object properties.
If you mean express tools layer toolbar, then type either expresstools or expressmenu in the command line.