If your ACAD folder is not there in the screenshot I added, it means the acad.cuix menu file is not loaded. You can right click on the Prrtial Customization Files folder up above it and load in the acad.cuix. It should be located in:
C:\Users\<username>\AppData\Roaming\Autodesk\C3D 2015\enu\Support
This is going to cause problems because acad.cuix is not meant to be a partial customization file. It contains workspaces. They should be ignored but you will get a million tabs added to your ribbon.
Also, you may have to add the Layout Tools ribbon tab to the contextual state folder by dragging and dropping in the CUI editor.
Bottom line is it is a pain. Looks like your AutoCAD profile got whacked or you logged in as a second user on the same machine and the secondary installer did a lousy job of buiding your profile. Or, you might have menuloaded the c3d.cuix and blew everything else away. Tough to say but it's certainly not looking like a standard out-of-the-box profile/workspace.
Mike Caruso
Autodesk Certified Instructor 2014
AutoCAD/Civil 3D Autodesk Certified Professional 2014, 2015, 2018
www.whitemountaincad.com