It is not impossible to uninstall windows media player 9. I would not understand why you would uninstall it, i use it all the time.
You do not need the system restore utility, or even to reinstall windows to get rid of it.
Open the "run" box from your start menu (or hit Windows-key + R to open it)
In the "run" box you type: (or cut and past)
RunDll32 advpack.dll,LaunchINFSection %windir%\INF\wmp.inf,Uninstall.NT
And hit enter.
Follow the instructions and there you go, windows media player 9 is uninstalled. I think it only works on windows xp.
Nice day all