You can use chain.c32 to boot boot sectors (hard disk boot sectors), a MBR of a drive, a partition boot sector.
You can also use chain.c32 to boot the freedos kernel(kernel.sys), msdos kernel (io.sys), Windows (NTLDR, SETUPLDR.BIN and BOOTMGR), grub4dos (GRLDR). The later usage of booting those files is that you don't need the correct boot sector code to boot those tools. You can just boot those files directly, instead of letting the boot sector code of for example Windows, load NTLDR.
If you want to boot Windows based ISO's directly (grub4dos or MEMDISK mapping), you need to include a driver (WinVBlock or Firadisk), else you probably will get the "Stop 0x0000007B" error:http://www.boot-land.net/forums/index.php?showforum=94
Download Ultimate Boot CD v5.0
Use Parted Magic
for handling all partitioning task: http://partedmagic.com/