This tutorial explains how to fix the Server Execution Failed error encountered when you are trying to open an audio or video file with Windows Media Player in Windows 8.
The first step is to close all running instances of Windows Media Player. Open the Task Manager and then go to the Processes tab. Search for any entry relating to Windows Media Player, right-click > End Task:
Open an elevated terminal and run the regsvr32 jscript.dll and regsvr32 vbscript.dll commands. Once the dll files have been successfully registered, close the Command Prompt and try to launch Windows Media Player again.