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You have a Late 2009 MacBook. As you could check in the link above, the Late 2009 MacBook isn't supported by Boot Camp to get Windows 8 installed. However, Boot Camp Assistant doesn't clarify this, because you can install Windows 8 (your system meets all the hardware requirements), but there aren't Boot Camp drivers for your computer, so Windows 8 won't work properly.
If you still wants to run Windows 8, install Parallels, VMware Fusion or VirtualBox, and install Windows 8 on a virtual machine. If you want to install Windows on Boot Camp, you can only install a 32 or 64-bit Windows 7 version
I have a same machine, managed installed win8 w/o bootcamp.
google macbook without bootcamp, and you will find the method.
my steps are follows,
1 boot with a CD (I forget the name, this is critical)
2 select USB with win8 bootable img preloaded.
3 following the win8 installation steps
4 download bootcamp 5, install drivers.
after everything done, I still have two unregon items in hardware, but it is OK.
Each time to boot, need to press down alt key.