'Unlocker' will help you to delete the actual files if it says access denied, file in use etc If that isn't the case. Maybe try delete sections at a time. Other option is if windows won't delete them try boot to a Linux based boot cd to delete it
Smashing the tracks out. Enzed asking you to remix one of his tracks is huge too man. Definitely good exposure. PS didn't need to say it but quality track as always