Well, the debug runtime is installed by the DirectX SDK along with a DirectX control panel which you can use to switch between the debug and retail runtimes.
If for some reason you don't have the DirectX control panel installed, then try googling for: directx.cpl
Place it in your Windows\system32 folder and then launch the Windows control panel in your start menu. You should then find the DirectX control panel icon.
If for some reason you don't have the DirectX control panel installed, then try googling for: directx.cpl
Place it in your Windows\system32 folder and then launch the Windows control panel in your start menu. You should then find the DirectX control panel icon.