To you or other people who might dont know yet.
when u tried to install win7 but u stuck in booting drivers.Here may be your solutions (read it carefully):
1.You can go to Bios settings ( shift click while clicking the shut down and on the laptop then as soon as the power turns on keep pressing the F2 button), it will bring you to Bios setup.
2.Now, navigate to advanced and look for USB3.0 support and u need to disabled it.
3.Go to Save & EXIT,down to 'Save Changes and exit' and press enter.
4.Insert the usb (with windows7 which is bootable) before you turn the power on.
5. Turn the power on but now u need to frequently press ESC button, it will bring bule box ( dont really remember)
6. Select your USB and press ENTER( not really sure too).
7. DONE!!! you may now finished. Go ahead and rock!!!
8. After u installed u may need to install service pack and drivers