This is the top of a Finder window. Those icons along the top are called the toolbar. I find it really handy to put items that you use a lot into this toolbar so that they are available from every Finder window.
When your computer first turns on it needs to load the system software (OS-X) and some settings from the hard drive. This is called ‘booting’. Boot time can slow down over time as you accumulate more software and hardware connected to your computer. Here are some tips to make your Mac boot faster.