You need Windows 8 to develop Windows 8 "metro" applications (now called Windows 8 UI Applications, or Modern Applications...) you cant develop in Windows 7.
MCTS - .NET 4.0 Windows Applications
MCTS - .NET 4.0 Data Access
MCTS - .NET 4.0 Service Communication Applications
MCPD - .NET 4.0 Windows Developer
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