Clay - which version of Windows are you on, and which version of Media Player? I'm assuming you mean that wmplayer.exe is showing as a process, correct?

Are you using WMP 11?
Do you have mini player enabled?
Do you have folder monitoring on?
Media Sharing?
Windows Media Player SideShow gadget?
Do you have any applications, plugins, or gadgets that use WMP API or anything like that?

There was an 'old' problem with VISTA and WMP 11 if I recall correctly, but that was fixed in a patch fairly quickly. Have you updated WMP to 12?

I also know the virus known as 'iTunes for Windows' had a bug that use to cause havoc with WMP, but I think Apple might have actually fixed that (surprisingly).