Originally Posted by PipeDreams
If you want to have a multi-boot system you will need something other than ntldr(windows booter) in the MBR.
This is a bit of an off-topic nitpick. In windows, the boot code in the mbr loads ntldr. You can install grub in the mbr and have it chainload (to ntldr) to boot windows.
ntldr is not in the mbr in windows.