wmplayer.exe is the executable for Windows Media Player, which is an application used for playing most audio files, viewing most video formats, and audio/video streaming. "This program is a non-essential system process, but should not be terminated unless suspected to be causing problems. "
Non-system processes like wmplayer.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that over time your registry suffers fragmentation and accumulates invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues