Visual Studio 2008 does not attach to w3wp.exe automatically on debugging IIS7

Question

All of a sudden my breakpoints are not being hit when I start an ASP.NET debug session in Visual Studio 2008. I am using IIS7.

I have to manually attach to w3wp.exe process for my breakpoints to be hit. However, I have to do this every time I start a debug session.

Does anybody know how to resolve this issue? Have I unintentionally changed a setting somewhere?