I am no computer wizard. When I first encountered W8 on my new laptop, I explored ways of loading W7 on the W8 laptop.
I read something that indicated that W8 could be downgraded to W7 only if you had the W8 Pro version installed.
That version I guess is typically a Corporate type software and Microsoft allowed the downgrade feasibility to avoid costly retraining thousands of employees in the W8 nuances at it's Corporate clients.
So, be careful when trying to install W7 on a W8 designed machine. There may be some glitches encountered.
That is why I use Classic Shell and await Microsoft's W8 enhancements this fall.
Also, I assume you know that to close those pesky boxes (apps) that appear on your screen, you place the cursor at the center top of the screen, left click and drag the top to the bottom until it disappears.
That should then return you to the Metro screen where you can select "desktop" to move onward.