After gone though screen shot you can notice that there is no Start Button or Program icon, instead will be a title that navigates you to other services.
According to Steven Sinofsky president of Windows division at Microsoft while speaking at D9 conference at Computex 2011 in Taipei:
“What we tried to do with Windows 8 is really re-imagine how to work with the PC, we looked from the ground up at how you interact with Windows, the kind of programs you can run and how you get those programs.”
“We were doubling the system requirements for a base-level Windows with every release, which turned out to be every three or four years. We looked at the ARM processor and what was available and we looked at the Windows codebase and realized they were in sync. When you look at the RAM usage, number of processes or disk blueprint, those are all the same as what you see on the current crop of slates.”