[This is preliminary documentation and subject to change.]
Recommendation (Designed for Microsoft® Windows® Logo)
Games should pause game play and stop playing sound when they receive WM_POWERBROADCAST sleep messages.
For a description of pretesting you can do to ensure that your application provides proper ACPI/OnNow support, see Pretesting ACPI/OnNow support.
For more information about the OnNow initiative and for OnNow technical specifications, see http://www.microsoft.com/hwdev/onnow.htm.