Black window after installing windows7 by using bootcamp (Macbook,Late 2008)

I'm trying to install Windows 7 on my Macbook Aluminium (Late 2008) , running Yosemite via Boot Camp.

Bootcamp warns: Boot Camp needs to update the USB drive before installing windows 7. The USB drive connected to this Mac contains a bootable volume. In order to install Windows 7 from the DVD, the Boot Camp Assistant needs to disable this functionality. No information on the drive will be removed, do you want to continue.

And after hitting "Continue", Bootcamp starts partitioning and Mac restarts.
But then it shows a black screen with a white underbar blinking.
When I shut it off and restart Mac with pressing option key, only my Mac HD and Recovery HD are shown, and Windows is now shown.

BOOTCAMP Partition has been made though.

I have tried many times removing partitioning, and starting with Boot Camp...

I have Windows 7 Home Premium 32bit (tried with 64bit) ISO in the external USB 2.0 hard drive ExFAT formatted (tried with MS-DOS FAT, didnt work).

Can anyone help me what I should do??