AFAIK opening up Windows Media Player while playing games will actually hinder performance, as it will take CPU cycles and RAM to keep the program open.
Windows Media player has nothing to do with driver's or ram (besides taking up ram when it's on). Driver's are handled by your operating system.
If anything, something like Gamebooster would do the job (it closes unnecessary services and programs when you want to play a game), however you could do these changes yourself, but gamebooster puts it in 1 nice little spot.
Hope this helps.