Can I Stop Windows Media Center (WMC) Services from Startup in Windows XP / 7 / Vista
Run System Configuration utility (MSConfig) and go to the Startup tab. You will find a list of item entries. You need to uncheck the ones that have “ehome” as the path to command line, like ehTray.exe. This prevents the WMC related services from running on Startup.
However, from my personal experience, to be on a safer side, it is better to disable the WMC services as mentioned in the previous post.
Read the main post if you still are unable to disable Windows Media Player.