Steps to follow:
Step 1 : Initially, Download the Rainmeter Software and install it.
Step 2 : Now download a skin, say Omnimo 4.1 for Rainmeter.
Step 3 : Install the skin i.e., double click Omnimo.rmskin file.
Step 4 : Once the skin is installed, run the rainmeter and you can have the tile based view of Windows 8. Now, you can customize the start screen like adding panels, arranging them in the order you wish etc.
This is it and you have Windows 8 Start Screen on Windows 7.
