How do I blur the entire screen in a Winforms program?

Question

Hello,

I am trying to come up with a way to blur the entire screen (all forms visible) on a WinForms program. I am using C# in VS2005. I have tried the code from this link:

.net - C# dialog form with blur background - Stack Overflow

...and it works quite well, however it only works for the active form, not for all forms visible. How would I adapt this code to work for the entire screen? I looked at
the Application.OpenForms[] controls, but I can only do one control.

Is there a more elegant way to do what I'm trying to achieve?