Well, Windows 8 is specially developed for touch screen devices like tablet. Windows 8 has most of the features for touch devices. Start button has been replaced by a new feature which cannot be accessed by the devices like a mouse. You must be using a tablet device for it.
Please don't respond to peoples inquiries, if you have no idea what you are talking about. The windows 8 "start" interface can be accessed by a few different methods without the need for a touch screen. To access the screen simply hit the "windows key" on the keyboard or hover in the lower left corner, and click. There may be other methods, but at the moment those are the only two I know of.