How does GRUB/GRUB2 move the Windows bootloader?
 

I find it very interesting that GRUB knows where Windows bootloader resides, How does it moves the code to an other area of the hard disk?

Boot code is at a specific location on any hard disk so the scripts check the locations.

Not sure what you mean here? Grub doesn't move the windows code, it locates it and chainloads it so the windows bootloader can boot the system. Someone else with a little more knowledge will probably come along and give you more details.

As I understand it when you install Linux it writes to the Master Boot Record, where the BIOS loads code from, and replaces Windows's record with a jump to wherever GRUB is installed. GRUB install searches for operating systems and adds them to a list so you can choose which to boot.