I GOT IT. it is c:/program files/common files/sdmpc.exe!!! (you may have a different drive letter)
Thank you so much everyone!!!
When you open it with ResHacker, there is a PNG file labelled 109. you can replace with the png file of your choice and it will load. To replace the progress bar, simply replace the bmp. This is sooooooooooooooo cool! wow!!! If you ask me, Stardock should make their MPC core skinnable. Then I wouldnt have had to go through all this trouble.
I have started a new revolution of hacking the MPC core!!! Someday in the future, Wincustomize will make a section of MPC core pictures!!! Yay!!!
MWAAAHAHAHAHAHHAHAH
THIS IS SO COOL