It seems that you want to know if the Windows Media Center is supported by the Slingbox PRO-HD.
As a matter of fact, it is supported by the Slingbox PRO-HD. However, you must take into account that the Slingbox might not work in a proper way on a Windows 7 64-bit computer. The following link will provide you with all the information about the Operating Systems and web browser supported versions:
Hope this helps!