Impossible to install Windows 7

Hi ! My friends have a MacBook white 2009. I try to install Windows 7 Ultimate (32 bits) on it, but it is impossible. First, the DVD (OEM) is rejected every time. Second, I did a bootable usb drive with my MBPr. But in his computer, BootCamp don't detect is like a bootable devise. Also, it is not detected in the boot menu (alt at starting). ------------I verify the permissions of the disk, verify the disk, manually partitionate the drive (75 go allocated for an MS-DOS partition). Nothing works Thanks to help me