ok so I found out how to make the changes for the background in WMP
download res tunner HERE:http://www.restuner.com/download.htm
go to windows_systeme 32 and open "MediaPlayer_10.dll". with res tunner
go to 265/5321.jpg and remplace the background with a new one"must be a jpg 800x600"
step 4:save your DLL with the background you choose with res tuner
step 5: replace the newly edited DLL with the old one (be sure to change the old one to MediaPlayer_10.dll_old)
so you can change it back if you like
and thats it! was very easy to do!