It Is In The Start Menu Start Menu\Programs\Startup
It's referred to as the WINDOWS key and is usually represented by the Windows logo from Microsoft and is usually located in the real estate between CTRL and ALT.
Go to the apple menu, choose about this mac, the version is listed under the apple logo.
Not sure about Mac OS X but, in Linux it depends on what desktop environment you use. Some don't use 'Start Menu's at all. I'm not sure they have names at all other than application menu/list.
To start a program click start, and then click the name of the program you want to open. The selection of the start menu that you will see displays the icons and names of the most recent and most frequent used programs. To open a program that you do not see on the start menu, point to Programs, and then navigate through the menus to the program you want and click it. When you open the program, Windows automatically displays it on the start menu.
submenu
menu bar
The menu that appears when you right click on something is called the 'shortcut menu'
Most modern Linux distributions do not have boot floppies to start the installation; they assume that your computer is capable of booting from a CD (which it likely is). Debian is one of the few exceptions. The boot floppies can be downloaded from the Debian website. Note that the latest release doesn't support this, but the older stable release does.Building your own Linux boot floppy isn't terribly difficult, but it will require you to compile your own kernel (the kernels found in most distributions are too large to fit on a single floppy). You would compile the kernel, put it on a floppy disk, add the SYSLINUX bootloader, and add a menu file for it. You would then add additional files for the programs and boot scripts, or create a separate floppy with the files, and specify that as the root in the bootloader (root=/dev/fda).
shortcut menu
The home menu is that screen full of icons that displays when the 3DS is switched on.
In the boot menu you might have a choice of Operating System (I do, on one of my computers that has both Linux and WindowsXP - when I start the machine the GRUB shows me a menu in which I choose OS)GRUB = GRound U Boot loaderWindowsXP is the operating system, it has to be running for any menu to show.