System.Core----core does not exist in namespace System


i get the message Core does not exist in the namespace System when i try to use WinMM code.

All i want is the "using xxxxx" so that PlaySound can be accessed. If I use NativeMethods.PlaySound I get the error message System.Drawing.NativeMethods is inaccessible due to its protection level. and another message that says NativeMethods does not contain a definition for PlaySound.

the VS IDE is very strict and therefore the examples should elaborate the "using xxxxxx" statement for the IDE. if I search the MSDN i get the link library is Coredll.lib. big deal. now what?

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